List of goofs/Season 2

Scary-oke

 * When Wendy enters the shack at the announcement of the after-party, she is wearing her name tag. However, when she is leaving with the crowd, her name tag is not seen.
 * When the agents pull up, there's a bumper sticker on the rear bumper. When they drive away, it's no longer there.
 * When Dipper and Mabel are in the attic, and Mabel is claiming that there is nothing left to discover about the journal, there are only watermelon seeds on the neck and sleeves of her sweater; the front of the sweater is completely missing the watermelon seeds.
 * In the shot of the teens dancing, Tambry is wearing her regular day wear instead of the party outfit shown earlier.
 * When Lee, Nate, Tambry, and Thompson arrive at the party, Lee is wearing a sleeveless shirt. In the next shot, it has short sleeves.  When all four are seen dancing, he is sleeveless again.
 * When Tambry takes a picture of Thompson with his shirt off, the photo is slightly different than the reality.
 * During the rap scene, the number of Sheriff Blubs' fingers changes.
 * Lazy Susan's lipstick is missing in two scenes; one where she is entering the Mystery Shack with a pie, and when the ground is shaking from the zombie invasion.
 * The mess Grenda makes moves when she, Candy, and Mabel are dancing.
 * The spell Dipper reads from the journal has some Latin words, but are in the wrong declensions and genders.
 * Dipper mispronounces the spell he uses to raise the dead. In the journal, the incantation's second line reads "Diablo Dominium," but Dipper reads it as "Diablo Dominus."
 * Agent Trigger and Agent Powers switch places from when Dipper says the curse to when the zombies attack.
 * The karaoke machine changes places, and even disappears, many times when the zombies are starting to attack the shack.
 * Mabel's cowlick color changes multiple times, from brown to pink, when the zombies attack.
 * During one of the shots after the zombies destroy the golf cart, some colored lights can only be seen for one shot above the horde with Soos, as well as some orange and yellow flags.
 * When Stan is talking to himself about Dipper in his underground lab, the desk, which presumably showed Stan's tattoo, looks different. The altocumulus cloud-looking symbols are upside down and connected to the main body of the symbol, and there are circles in the middle of the outward pointing arrows.
 * When Stan sees himself in the reflection of  1' s hand, the reflection is not reversed.
 * In the same scene, 1 is shown with a monocle and ripped back cover, which are unique to 3.
 * The glass from the window that Soos smashed disappeared from the floor when a zombie breaks through the wall.
 * The TV was on a static channel before and when Soos sits down he says its on Gossiping House Wives.
 * Journal 3 claimed that zombies were invincible, except when subjected to a three-part-harmony. However, Dipper, Mabel, and Stan kill many, usually by decapitation, skull-crushing, or severing their spines.
 * Stan & Mabel's microphones aren't plugged in when they are singing.
 * Whenever Love Patrol Alpha starts to sing together and shatter the zombies brains, the karaoke machine says "We're taking over the dance floor! (Instrumental.)" But whenever it says instrumental, that's the chorus.
 * During "Taking Over Midnight," when the three are singing "We're queens of the disco!", Dipper steps up, followed by Mabel and then Stan, but when the camera zooms out, the order changes to Dipper, Stan, and then Mabel.
 * After singing "Taking Over Midnight" by &NDRA, Stan's fez appears while yelling "Deal with it zombie idiots!" It then disappears again in the next shot.
 * At the end of "Taking Over Midnight" BY &NDRA, when a zombie goes to attack Dipper, all of their microphones are suddenly gone from their hands and are not on the rooftop.
 * The sun started rising after they sung "Taking Over Midnight" by &NDRA but the party started at 8:00 PM, so there is no way the party could last about eight hours.
 * Stan activated the Universe portal in "Gideon Rises" by pushing the lever in front of it to the left. But during a full shot of the portal room at the beginning of this episode, the lever is seen facing the right.
 * When Agent Powers and Agent Trigger look at their screen after Stan activates the portal, Agent Powers sits left and Trigger sits right. They change while the map appeared.
 * When Stan is looking at the screen in the cold opening, the glow of the screen on Stan's face is not backwards. Both the screen and the glow on his face are able to be read from left to right.

Into the Bunker

 * Wendy has two left arms when she reaches for some popcorn.
 * In the same scene, in one frame, Dipper's mouth is completely displaced from his face.
 * The stuffed animal Wendy pulls from her bed's corner wasn't there in the previous scenes, nor shows up again in the following scenes.
 * The map of Gravity Falls changes in size.
 * Wendy didn't hear Mabel and Dipper talking when they were only a few feet apart.
 * Wendy magically ended up next to Dipper after he was done pacing.
 * Even though the Shape Shifter turned into a Hide Behind, the journal had no clear picture of it.
 * The Shape Shifter as the rolling thing chasing Wendy and Dipper was much closer than a few scenes later.
 * The scar from Wendy's ax disappeared when Wendy and Dipper are pushing the Shape Shifter into the freeze chamber.
 * Wendy's torn sleeve is only a few centimeters shorter than the non-torn sleeve.
 * At the end of the episode, several fireflies are seen buzzing around, despite the fact that fireflies are not native to Oregon.
 * In the scene in which Dipper is going to find another way out of the bunker, he grabs Wendy's right hand. In the following shot, he is holding her left hand.
 * Dipper and Mabel were sitting in the middle of the log, but when it zooms out, right before Soos sits down, they're sitting at the far right.
 * When the Shape Shifter drops Journal 3, Dipper walks up to the Journal and picks it up. In one frame, the Journal lifts itself closer into Dipper's hands without Dipper touching it yet.

The Golf War

 * In the previous episode, the Mystery Shack was in renovation, and the "S" should have been put back to its spot before "Headhunters".
 * After Soos draws the w-neck, the marker he used disappeared from his hand.
 * While Pacifica is insulting the Pines family, Dipper does not have a putter, but when he decides to make a comeback, he is leaning on a blue putter.
 * The right wing of the golf cart driven by the royal employee goes through the lamp post as he drives around it.
 * The golf car has no dents after the employee drove into the lamp post.
 * When Dipper first hears noise coming from inside the windmill, the wood covering has a design on it. When he approaches with Mabel to tear it off, it is plain.
 * The map of the course is not an accurate representation. For example, the windmill and the pirate ship are close together, but in the map they are widely separated.
 * When Dipper is talking with Mabel, his mouth is over his vest.
 * After Mabel throws her club, it disappears. When Pacifica walks towards the Pines, it reappears.
 * Dipper's club was nowhere to be seen, then he receives it after he told Mabel to grab her club.
 * When Dipper takes off the panel of the windmill, he's to the left of Mabel. But when it shows them a few frames later, they're swapped.
 * The lilliputtians that grab the golf ball make the ball appear.
 * All the other golf balls disappear when the lilliputtians demonstrate how they made the hole work.
 * When Robbie writes "wieners" on the castle, it was much further down than when the knights entered the episode.
 * Also, the castle comes down much further than in the beginning of the episode.
 * The part in Mabel's hair changed from right to left when Pacifica and Sergei entered the mini-golf course.
 * Big Henry's tool is nowhere to be seen after he takes the golf ball.
 * When the liliputtians take Pacifica, they are wearing gloves and sleeves, but before and after they aren't wearing them.
 * When Dipper and Mabel see Pacifica being held captive, Mabel's sticker is on the opposite side of her sweater.
 * Pacifica's PutPut comes out of no where after Mabel unties her.
 * After they break out one wing on the golf cart is fine and the other is destroyed, but both sides should be destroyed.
 * When Mabel is apologizing to Pacifica, in one frame, her braces remain the way they would be when her mouth is wide open, even though her mouth is partly closed.
 * Electricity from the elevator button being pushed would've ignited the gas leak causing an explosion

Sock Opera

 * When Dipper and Mabel are leaving the Gravity Falls Library, they forget the laptop on the desk.
 * Gabe's piano disappeared when he was talking to his puppets.
 * The book that fell on the floor at the library disappeared when Mabel was talking to Gabe.
 * After Bill tells Dipper he's been keeping an eye on him, Dipper's eyebrows and eyes continuously appear and disappear.
 * When Gabe visits the Mystery Shack, Mabel's braces disappear when she begins laughing nervously.
 * When Bill first possesses Dipper, his eyebrows disappear.
 * When Bill in Dipper's body stopped smacking the drawer onto his arm he had two forks sticking out of it, but when he left they disappeared.
 * When Mabel answers the dressing room door, Gabe is shown carrying a bouquet of pink flowers, however when he enters they disappear.
 * During the show, when Dipper (as a ghost) is doing the kiss scene of puppets Mabel and Gabe, there is a heart-shaped background close to the socks, but when the camera changes the background is no longer there.
 * In the theater, Wendy and Bill are sitting in the same seat at first, with exactly one free seat to their right. A few seconds later, they are sitting in two separate seats and there is still a free seat to their right.
 * Several times throughout the sequence where Bill possesses Dipper, the password bars disappear.
 * In the attic after Bill possessed Dipper, he was faded like a clone, but his hat wasn't. When Bill as Dipper was outside, all the colors were normal.
 * While Bill in Dipper's body was speaking to Soos outside the Mystery Shack, his eyes disappear in one frame
 * The Journal wasn't on stage after Dipper gets his body back.
 * Several times in this episode, Bill's top hat and/or cane disappear (however this may be because of Bill's pre-addressed ability to hide them behind his body, though he is never seen to move them).
 * Before Bill forms the screaming head, his hand is cut for one frame.
 * When Mabel is sitting on the floor, singing a song about Gabe, her legs are cut.

Soos and the Real Girl

 * After Soos leaves work and it cuts to "First Person Puncher," everything is pixelated; the TV, walls, figurines.
 * During the scene in which Soos is first trying the game and says "I'm learning, and games are making it fun," his eyebrows are misplaced for a fraction of a second.
 * When dyeing Abuelita's hair, the foil is originally silver, but when she walks away it is bright orange.
 * The "HE's GOT ATTI-CUBE!" poster in the door of Soos' room shows a prominent COOLCUBE logo in the upper right corner when we first see it.  In subsequent shots the COOLCUBE logo is missing.
 * When Soos runs into the gaming store, the box he finds Romance Academy 7 in isn't visible.
 * The note that says destroy at all costs was not on Romance Academy 7 ' s box when Soos first reads it.
 * The cans of Pitt Cola were not on the floor when Mabel and Dipper entered Soos's room or when they left, but were there when they told Soos that he needs to get to the mall.
 * During the scene where Mabel and Dipper drag Soos away from his room, Mabel's cheeks have outlines on them for two frames that flicker back and fourth.
 * When Soos is talking to Melody for the first time, despite the fact that she's in the foreground in one shot, Soos's arm moves over her hair.
 * When the door to Hoo-Ha Owl's Pizzamatronic Jamboree closes, it is covered in pits before it is hit by any skee-balls.
 * In the scene where Soos and the others are hiding behind the toppled arcade cabinet, the character peeking over the fortress wall on the side of the cabinet changes from a peach color to red in one short scene.
 * In Hoo-Ha Owl's Pizzamatronic Jamboree, the graphics for Star Battle appear on the unit for First-Person Puncher.
 * When Dipper tricks the bear animatronic into hitting the win button, Mabel's shoes weren't in the shoe holder. Later, when they were caught, Mabel's shoes are back on her feet.
 * Mabel buys a sticky hand from a vending machine. The containers are all clear with colored lids, but she's shown opening a plastic Easter egg.
 * The unnamed man in red appears in the mall once in one area and then another place in a fraction of a second.

Little Gift Shop of Horrors

 * While Stan is attempting to get the traveler to come into the Mystery Shack, his mouth overlaps his nose for a frame.
 * While Stan is attempting to get the traveler come inside, his mouth disappears for one frame.
 * When the Pines first approach the Hand Witch's table, the stall in the background says "Lots O Pots." Later is changes to "Pots Aplenty."
 * When Stan mocks Dipper's concern about a curse, the stalls in the background change. Instead of Lazy Susan and Old Man McGucket's stalls, Pots Aplenty and Cheep Cheep Tires appear. Additionally, they are transposed (Pots Aplenty was on the right of Cheep Cheep Tires next to the witch's stand).
 * When Grunkle Stan first grabbed Waddles when he started to tell "Abaconings," the Summerween basket is standing upright. After he put Waddles down on the floor, the Summerween basket is knocked over, and the candy inside it is spilling out.
 * During the scene in which Mabel and Dipper first see that Waddles is now a genius, the machine that he rolls in on is layered incorrectly with a nearby pile of books.
 * When Waddles shows Dipper and Mabel the What-the-heck-ahedron, the stack of books was on the opposite side of Waddles, the stuff that fell of the books disappeared, and the What-the-heck-ahedron appeared.
 * Dipper is floating when Mabel enters the shed, and the ladder isn't there.
 * The cheapskate's box changed locations.
 * When Grunkle Stan first throws the grappling hook over the gate, it lands on the ground. When the next shot shows Dipper, Mabel, Stan, and Soos walking up to the front door, the grappling hook is still on the ground, when it should be hooked into the top of the gate, which makes it possible for them to climb.

Society of the Blind Eye

 * Lazy Susan's apron stain appears on the right (her left) briefly when her hands are being clasped to the chair. Not long afterwords, when her hands are being unclasped, the stain is again incorrectly depicted on the right.
 * McGucket had nowhere to hide under the table in Greasy's Diner.
 * Lazy Susan's purse strap turns from purple to yellow.
 * Even though Carson was with the other gnomes, in the last shot he takes on more of Shmebulock features.
 * When Blind Ivan says, "It is unseen," his tongue makes the motion of an "L".
 * The first time the photos of "suspicious townsfolk" are shown, |Alex's  photo isn't there.
 * The large piece of paper in the middle of the "who is the author?" display disappears the second time the board is shown.
 * When Mabel is talking to Dipper about Mermando, the picture of a "3" on Journal 3 looks more identical to a "5".
 * The marker Mabel uses to write "Failed" above her summer romances, wasn't in the previous scenes, and is not in any of the following scenes.
 * During the scene where Dipper tries to deduce who the author is, the photos of suspicious townsfolk vary between having writing on them and not throughout the scene.
 * When the group confronts McGucket, Dipper shows him the Journal, but when the screen pans in, it shows Wendy's arms holding the Journal. It switches back to Dipper when the screen pans out again.
 * When Mabel is talking to Wendy about her failed romances, they change positions so that they're near a billboard, but in following and previous scenes, no billboard is visible.
 * When Dipper views Robbie's memories, the tube isn't in the container.
 * When Mabel grabs the memory erasing gun, the bottom of the red glass section vanishes
 * All the members of the Society of the Blind Eye are the same height until they reveal who they are.
 * Blind Ivan's tattoo patterns change multiple times.
 * When McGucket grabs his memories, the label is swapped around.
 * When Mabel is entering summer romances into the memory erasing gun, her hand isn't moving the dial.
 * When Mabel and Dipper reveal what has bothered them, their arms are free of the ropes.
 * When McGucket walks towards Blind Ivan, his arm goes through his hat multiple times.
 * When Dipper erases the memories of the Society, Toby Determined and the Unnamed woman in blue are missing.
 * For a frame McGucket has two band-aids.
 * After they give Gabe buck teeth Wendy says, "Let's give him buck teeth"

Blendin's Game

 * During this episode's promo, Blendin Blandin yelled, "My time knee! Oh future dang it!" after he fell, but in the actual episode, he yelled, "My time knee! Oh time dang it!"
 * When Soos takes the candy from the vending machine, the candy he took out wasn't in the machine. The candy that Dipper and Mabel tried to get was fixed even though Soos didn't grab it.
 * When Dipper and Mabel look at Soos's drivers license, his wallet disappears.
 * When Dipper is holding Soos' driver's license, on the back, the magnetic strip is near the bottom, when it should be near the top
 * As a kid, Soos's voice alternates between high and normal.
 * In the cold open, Mabel's sweater does not have any graphic on it, but is later shown with a doughnut on it.
 * At the end of Globnar, cuffs appear on Blendin, though they were not there in the previous shot.
 * The postcard Soos is looking at is clearly of New Orleans, but in the next shot it has changed to a postcard for/from Las Vegas.
 * Toby's mouth is misplaced in his reflection.
 * When Dipper, Mabel, Blendin, and the guards go to the future, Dipper and Mabel are wearing handcuffs, but in the past they weren't.
 * The mirror reflects Toby as being much closer to it than he actually is. It also does not reflect the railing that is right in front of it.
 * The photo and signature on Soos' drivers license change drastically between shots.
 * Before the final challenge of laser tag, the scoreboard shows Blendin with 764 points but after the challenge, his score has changed to 763.
 * In the final Globnar scene, Mabel and Dipper keep switching places as they talk with the Time Baby about Blendin's fate and their time wish. Dipper is to the left of Mabel in one shot but in the next shot he's to the right of Mabel then back to the left in the next shot.
 * In several shots, the bandage on Stan's hand is missing.
 * When Lolph takes out the tablet, there's a crowd behind him. In previous scenes, other people in general weren't visible.
 * In the future, Lolph doesn't have shoulder pads. In the present, he does.
 * In Blendin's flashback, when he was carving his mashed potatoes, from a distance the potatoes aren't carved, but up close they look like Dipper and Mabel.
 * The time machine isn't visible before it was shown broken.
 * Soos's piano is completely changed between when it was is the hall and his room. Also, he never even brings the present into his room, and neither does Abuelita.
 * Blendin's spear isn't in the previous or following scenes.
 * The time baby's mouth is clean a scene after the crowd is cheering for Dipper and Mabel.
 * When Dipper and Mabel came back to the present, they are a lot dirtier than they were in the future.
 * The postcard from Soos's dad looks brand new before he makes the time wish.
 * In the image where Dipper and Mabel are being chased by Blendin on top of a massive clock, Mabel is missing her braces.
 * The postcard from Soos' dad has no name on it, yet the mailman knows specifically who to give it to.
 * At Mr ZZZ's Mattresses, in the initial wide shot, the man screen right has both arms attached to his left shoulder. The two characters on the left are identical to their future selves.
 * When Abuelita first has the cookies they are shaped like dinosaurs, later when Dipper and Mabel look at Soos through the window the cookies are normal shaped.

The Love God

 * Right after the cold opening, when the group finds Robbie in the grave, the pine tree on Dipper's hat is missing when the scene is shown from above.
 * The sponge that Thompson licked wasn't in the previous or following scenes.
 * Next to the dug grave where Robbie is mourning the break up with Wendy, there is a grave that says 1989-1971, suggesting that the person was born in 1989 but somehow died in 1971.
 * The folds on Mabel's happiness chart disappears when the giant bird tries to eat Robbie.
 * In the scene where Stan is sewing a rainbow afro on a stuffed gorilla, the can of Pitt cola is initially miscolored, but is back to its regular color when it gets knocked over.
 * The bandage on Stan's hand is missing in a couple of shots, but reappears again.
 * In one shot when Stan is holding his crossbow, the bandage on his hand is colored black.
 * When Stan grabs his crossbow and aims it at the hot air balloons there are other weapons in his toolbox. But when he talks to Soos, the toolbox is empty.
 * Robbie's pictures from a little kid to how he is now contradicts with what young Robbie was shown to be like in "Blendin's Game."
 * The boxes that Wendy and Tambry are sitting on were turned, then strait and then turned again.
 * In the diner, Robbie's belt appears blue.
 * When the teenagers are cheering on Dipper for his idea to tape snacks to Thompson, Linda Cardellini says "Well done" but Wendy's mouth doesn't move (nor does Tambry's).
 * When Tambry sits down in the booth at the diner, she puts her purse on the ground next to her, but in the next frame it is gone. When she is about to leave she picks up her purse, which was on the seat to the left of her.
 * The mustard on Robbie's jacket sleeve disappeared despite the fact that he didn't lick it all off.
 * When the Love God first enters the diner, there are a few frames where he has a double chin (as an animation error).
 * In the scene where Tambry eats the food with the love potion, Tambry's hair is parted to the right instead of the left.
 * In the scene where Mabel tells Wendy and her friends about Robbie and Tambry, when Mabel first unfolds her happiness chart, Lee's face is not completely drawn for a frame.
 * When Nate says Tambry's name (after learning about her and Robbie), his mouth is missing for a frame.
 * After Mabel and Dipper steal the anti-love potion, it still appears in the Love God's belt when he confronts the two, and the potion remains visible in the belt while another anti-love potion is held by Mabel, Dipper, and the Love God.
 * After Dipper catches the anti-love potion Mabel throws to him, once he gets on stage, it is no longer in his hands.
 * When Stan's hot air balloon initially rises, the ropes connecting the ballon to the basket are not seen - only the balloon and the motor.
 * The mat Charlie and his mother are sitting on disappears when the shot widens to show the Stan balloon looming towards them.
 * The banner reading "I EAT KIDS" should not be able to stay up above the Stan balloon because no additional balloons are attached to hold it up.
 * When the Love God gets back the anti-love potion and talks, the anti-love potion looks much bigger than the potions on his belt.
 * After the group sees that Thompson is being chased by the security guards, they are on a hill overlooking the concert. However, in the next shot after Thompson is being hit with brooms, they are standing in front of stands.
 * Stan is shown with two hair pieces standing at the back, but after recovering from the balloon collapsing on him he is shown with three hair pieces standing at the back.

Northwest Mansion Mystery

 * When sitting in the recliner watching TV, there is a pizza box next to Dipper, but in the next shot it's gone, replaced by a can of Pitt Cola.
 * The appearance of the Northwest Manor is different than when it was seen in "The Golf War".
 * When Dipper first answers the door when Pacifica arrives, he is wearing his socks. When he finally agrees to help her, he's wearing his shoes.
 * When the butler pulls the lever to open the gate, the visible gear mechanism does not turn.
 * When Mabel first walks into Northwest Manor there is a glue gun stuck to her dress, but in the next shot of her it's gone. It doesn't return for the rest of the episode.
 * The description of Marius von Fundshauser in the guest list at one point reads "Marius Marius von Fundshauser".
 * The party's guest list has pictures of four people on each page, and each text box describes the people on each side of it. Marius' box only describes him, and not the woman on the other side of the box.
 * Grenda has two ponytails for a few frames before she makes the truce with Candy and Mabel.
 * When objects are flying around Pacifica and Dipper, Dipper is no longer wearing his backpack.
 * The ghost lumberjack shows up to the original party with a bow tie in his beard, but when he turns back towards the manor, it is gone.
 * When the ghost laughs and his beard blazes before he tricks Dipper into releasing him from the silver mirror, his mouth overlaps his nose.
 * Candy drips cheese onto the pastries, but later, when she is talking to Mabel, there is no trail of cheese near the fountain or on the pastries. Also, the pastries' appearance has changed.
 * When Grenda approaches Marius von Fundshauser to pretend that something is on his shirt, a yellow stain can actually be spotted on his shirt momentarily.
 * Only a few people are holding glass of apple cider before Preston Northwest gives a toast, but after Preston's glass breaks, everyone is holding a glass.
 * Duchess Wibblebip turns to wood while spitting out a drink, which also turns to wood. However, depending on the shot, the wooden drink appears and disappears.
 * The wooden people change positions several times.
 * When Dipper is turned into wood, his bow tie isn't tied. Later, when Pacifica looks at him, his bow tie is tied and when he turns back to normal, his bow tie is untied again.
 * Like with the butler, when Pacifica pulls the lever to open the gates, the gear mechanisms don't move.
 * The ghost burns the Northwest family portrait, but when he is looking out the window at the people coming through the gate, the portrait is perfectly intact again.
 * When the wooden people return to their normal selves, the cider fountain in the background is frozen still.
 * When Candy, Mabel, and Grenda hug Candy's head spins in an almost full circle.

Not What He Seems

 * When Grunkle Stan is talking Dipper and Mabel at the start of the episode, Dipper and Mabel changes places.
 * As seen in "The Inconveniencing" the ice box on top of the roof of the Shack has an opening lid. When Dipper takes a popsicle out of it, it is closed.
 * While Agent Powers is telling Dipper and Mabel about the doomsday device, Dipper is to the left of Mabel. It then cuts to a close up on Agent Powers. When it cuts back to Dipper and Mabel, they've switched places.
 * When Dipper and Mabel find the security footage, their reflection in the screen isn't reversed.
 * At first Stan's suit is buttoned up, but then it's unbuttoned, then it's buttoned again, then it's unbuttoned again, then when Stan goes to refresh his soda, it's buttoned again.
 * While a gravity anomaly is in progress, the coffee begins to come out of the mug in a solid block, although it is a liquid.
 * When Stan gives the taxi driver $100 his bandage is missing.
 * When Stan comes into the portal room the door is open, but in the next frame it's closed, then its open again.
 * When Stan is reading Journal 1, you can see a monocle. Journal 1 doesn't have a monocle, Journal 3 does.
 * The restauraunt employee somehow handed Soos his meal when he was still at the ordering machine.
 * All three journals were placed by Dipper in the configuration to show the blueprint for the portal, so Journal 1 was in the room outside of the portal room the entire time, but as Ford is walking out of the portal, he places his hand on Journal 1 and places it in his pocket.

A Tale of Two Stans

 * In "Not What He Seems," the left sleeve of Stan's coat is ripped by a tree branch. However, in this episode the tear isn't seen.
 * When Stan moves to punch Ford, his bandage disappears and reappears the next time his hand is visible.
 * Ford writes in Journal 1 although that wouldn't be possible because it was shown later in the episode that Journal 1 had no pages left in the book.
 * In Anomalous Phenomena, the book of anomalies Ford reads in college, the pages with the two-headed ducks and cats call the condition "polycephany," when it is supposed to be correctly spelled "polycephaly."
 * Ford instructs the recently memory-wiped agents, Trigger and Powers, using a few of Mabel's drawings as decoy paperwork. While doing so, the crayon text "What hath science wrought?" on Mabel's self portrait vanishes and reappears.
 * When Stan was escaping the angry customers in New Jersey, he is driving in the wrong direction and would have crashed his car into the beach instead of driving through town.
 * When Ford restrains Stan, a black, upside-down version of his glasses appears above his normal glasses.
 * Near the end of the episode, Ford has changed out of the clothes he wore in the basement, and into his regular ones. However, the clothes still retain the black color pallet, and only take on their normal ones in the next scene
 * Ford is shown writing with both his left hand (when they find the shipwreck when he and Stan are kids, and he leaves their names, and when he is writing in the journal in the present) and his right hand (when he is drawing in his notebook when Stan introduces him in his story, and at various times in school). Either he is ambidextrous, or this is an oversight.

Dungeons, Dungeons, and More Dungeons

 * In the scene when Stan is immitating Duck-tective he is seen with a cleft chin like Ford.
 * When Dipper explains the rules of Dungeons, Dungeons, and More Dungeons to Mabel, during the close up of Mabel's face the color of her sweater's collar, which is supposed to be pink, changes to purple.
 * Mabel's letter to her parents says, "just yesterday gravity reversed itself." However, in "Not What He Seems" Stan says that it is Saturday, and in this episode Mabel says they are having a lazy Tuesday.
 * Many other errors occurred during Mabel's letter writing. After Mabel wrote, "Just yesterday, gravity reversed itself, almost destroying the universe and totally wrecking the whole town!" it cuts to the TV. When it cuts back to Mabel, that portion of the text had disappeared and Mabel was writing, "But the coolest part of the summer was when Gruncle Stan's twin brother came out of this portal thingy" in the place the text was previously. In addition, Mabel said "Now we have two Gruncles for the price of one!" but didn't actually write it down, but when in cut to her picture, it was written next to it. Furthermore, the ink that the pen used was clearly shown to be pink, until it zoomed in on her picture, where the pen started writing in blue ink instead.
 * Mayor Beffuftlefumpter's name is misspelled as "Mayor Befufflefumpter.
 * When Soos walks behind Dipper after he explained "Dungeons Dungeons and more Dungeons", Soos was not wearing his "FCLORP" wristband.
 * While Stan is stapling the turkey head onto the beaver's body, his burn mark is shown on the left side of his back.
 * Mabel claims to have eaten the Cheese Boodles without her hands. However, cheese powder can clearly be seen on her fingers.
 * When Stan swats the fairy on his back, she sticks to him and glitter splatters on the back of his suit. However, in the next frame, the back of Stan's suit is completely clean.
 * When Mabel is talking to Dipper while Dipper is designing his dungeon, Mabel has a hairband in her hair, then, when she starts talking about how Dipper is spending a lot of time with Ford, she isn't wearing a hairband, finally, in the next scene, she is wearing her hairband.
 * When Stan places his gum on the opposite side than the 38 on the dice, it becomes invisible when he rolls it.
 * Dipper and Ford throw the "Death Muffins" into the Impossibeast's mouth, causing them to lose the muffins. When they return to normal size, they are still holding the muffins.
 * When stan is shaking the dice in his hand, It sounds as 2 dice are in there rubbing together. However, only 1 die was in his hand.
 * Right before the commercial break, after Mabel, Grenda, and Stan are loking at the hole the griffin made in the wall, Mabel and Grenda are wearing their Duck-tective hats. However, after the commercial break, they are no longer wearing the hats.

The Stanchurian Candidate

 * Tyler throws his hat into the ring (and apparently so does Sprott, though this isn't seen) but when we see the crowd, both Tyler and Sprott are still wearing their hats.
 * Bud Gleeful punches the map of Gravity Falls, ripping the part where the Mystery Shack is but when we see the map again the place where the Mystery Shack is isn't ripped.
 * Soos has "STAFF" written on the back of his shirt but when he's on his hands and knees after Mabel turns off the mind control tie the back of his shirt is blank.
 * When Stan enters the diner, Lazy Susan is there. A few seconds later when the angle changes she is gone.
 * When Stan asks "just the ladies" to cheer for him, an old man cheers for him as well.
 * When Dipper is in the diner and gets mad at Stan for refusing to wear the tie, the rest of the customers in the diner seem to disappear.
 * When Dipper reveals to Stan that the ties were made to control him, both ties are exactly the same.
 * When Soos is on stage waving at the audience, he keeps waving despite Dipper (wearing the tie) having stopped waving.
 * Stan puts on the sash Mabel knitted for him upside down but once it's on him he's wearing it right side up.
 * There's a mug on a mantel when Stan is sitting on the chair but when he gets up to leave the mug is replaced by a head.
 * At the town meeting, Robbie is initially seen sitting in the back next to his parents, but when everyone gets up to leave, he is in the front row next to Lazy Susan.

The Last Mabelcorn

 * When Dipper puts on the helmet on Ford's head, the repeat of the thought "I miss Dimension 52" is misspelled as "I miss Dimention 52."
 * When Ford puts the Project Mentem helmet on Dipper, the switch on the top is silver. When Dipper puts it on Ford, the switch is black.
 * A symbol in the cryptogram is misplaced on the ancient wall Ford found, making the word decode to "FOOJISH."
 * When Wendy, Mabel, Candy and Grenda enter the gates to the unicorns, their positions (relative to each other) changes between some of the frames. In one frame, the order is Grenda, Candy and Mabel (left to right) and in the next frame it is Mabel, Candy, and Grenda (left to right).
 * The treasure revealed by Grenda contains a pair of dice, each die shows two sides with a repeating number symbol.
 * When Dipper and Ford were talking, after Dipper tried to erase Bill out of Ford's mind, the number of fingers on his left hand changes to five for some frames.

Roadside Attraction

 * In the first shot of the Mystery Shack after it has been pranked, one of the grafittis of "You Stink" is in neon green, but when it is next seen in a close-up, it is a faded brown color.
 * When Stan and Dipper are in the hot tub, Stan opens a can of Pitt Cola and Dipper's hands are empty. In the next shot (a wider shot) Dipper has a can of Pitt Cola in his hand, too.
 * When Mabel is eating marshmallows there is another set of teeth overlapping her top row of teeth.
 * During the girls' game of Truth or Dare or Don't, after Candy confesses to her crush on Dipper, Mabel says "No" and Candy says "Yes." In the shot when they cut to Candy, her hair is missing from below her ear.
 * The sign on the large raccoon at Mystery Mountain Mummy Museum reads FIRE RETARDANT RACCOON but its recorded message identifies itself as FLAME RETARDANT RACCOON.
 * One of Dipper's pictures of Wendy is a selfie of them. In the selfie, Dipper is missing the pine tree on his hat.
 * When Soos is saying that was fun for 78 hours his mouth disappears for one frame.

Dipper and Mabel vs. the Future

 * When Stan says, "the future," with Soos, Dipper, and Mabel, he has a cleft chin like his brother Ford.
 * Lee and Nate change up the board outside of the school by rearranging the letters in "SAWDUST INHALATION DRILL- 8:00 GO FIGHTING BEAVERS!" to "NO ESCAPE." However there is no "C" or "P" in the former message, so they wouldn't have all the letters needed to write "NO ESCAPE."
 * When Mabel and Blendin are laying on the ground, their shadows go in different directions.
 * When Bill leaves Blendin's body, Blendin's body falls and lands on top of the broken pieces of the glass orb that used to hold the rift. The next scene shows Blendin's body laying besides the glass orb's remnants.
 * After releasing the rift, Blendin removes his goggles to reveal Bill's deception and then collapses. However, the next shot of Bill rising above the bodies shows Blendin still wearing his goggles.
 * When the citizens of Gravity Falls notice the arrival of Bill, Lazy Susan has both eyes open naturaly, (which can't be done without her holding her closed eye open)

Weirdmageddon Part 1

 * After Gompers eats a part of Stan's hat, Stan drops his hammer and yells at Gompers. Then the weirdness wave comes, it cuts to Gompers growing, and then it cuts back to Stan, except the hammer is no longer present.
 * When Stan starts yelling and running away from Gompers, his yells do not sync up. His mouth is closed when a yell is heard.
 * Throughout the episode, the number of Gideon's fingers changes between four and five.
 * After the enlarged Gompers eats out a part of the prison, Gideon's finger painting is shown, except the pictures of Mabel have changed places and the word "Love" is no longer present.
 * During the scene where the discount auto mart warriors are chasing after Dipper and Wendy, one of the prisoners is eaten by The Horrifying Sweaty One-Armed Monstrosity. However, the same prisoner who was eaten can be seen when Dipper changes Lil' Gideon's mind about Bill Cipher.
 * After Dipper and Wendy find Soos, Dipper picks up his hat off the ground. However, the hat was in the car and was never shown to have fallen out.
 * When everyone was running from Bill, Nate was duplicated.
 * When Bill was fastly coming up to Dipper, the 3 on Dipper's journal disappeared for one frame.

Weirdmageddon 2: Escape From Reality

 * When Dippy Fresh high fives Soos, he is wearing a skateboarding helmet, but in the previous and succeeding shots, he is not wearing a helmet. Oddly, he isn't even wearing the helmet when he is actually skateboarding.
 * When the younger Dipper shaves part of his head in the flashback, his birthmark is not visible.
 * In one of the flashbacks, when Mabel gets gum stuck in her hair, it's on her left side, but when Dipper gets her to shave it off, it's on her right.
 * In Bill's "throne of frozen human agony", Manly Dan is in a different pose than when he was frozen.
 * Similarly, Lazy Susan is in a different pose than in "Weirdmaggedon Part 1."
 * Manly Dan wasn't shown being taken away by an Eye-Bat, but he is in Bill's "throne of agony" before Sprott was.
 * In one shot where Bill is starting to yell, Teeth is missing a tooth. In the next scene when everyone's running away from Bill, the tooth is back in his mouth.
 * In the first flashback, despite the wind blowing to the right, the flag at Eggbert Elementary blows to the left.
 * After Wendy puts her ax away, it disappears.
 * When the Multi-Bear exits from the bathroom and says his line, Stan's neck is not fully drawn.
 * When Dipper, Mabel, Soos, and Wendy come to the shack, there is no golf club on the floor. However when Dipper reaches to get it, it appears on the floor.

Weirdmageddon 3: Take Back The Falls

 * When Stan switches clothes with Ford, sometimes it shows Stan with 6 fingers instead of 5.
 * There is also a scene where instead of wearing black gloves, Stan's hand is gold.
 * When the refugees are discussing how to save Ford, Wendy is both huddled with McGucket, and standing behind Stan.
 * Creggy G. is both in the Mystery Shack among the refugees and is in Bill's Throne.
 * Pacifica is seen standing on the cipher wheel in a scene before actually stepping on her symbol in another scene.
 * The moving truck is not seen in the shot after it appears even though the next shot should show it.
 * The No Animals Allowed sign that appears on the bus does not appear until after Waddles is put on the bus.