Bart Gets Hit By a Car - S2-E10
Revealing mistake: After Marge has been in court, Mr Burns' lawyer says "Thank you very much Mrs Simpson", and when he does it, the top of his head above his glasses is less pale than the rest of his face.
Revealing mistake: If you look carefully in Mr. Burns' surveillance cameras, the workers are identical. (00:02:50)
Bart's Friend Falls in Love - S3-E23
Revealing mistake: When Bart tells Otto not to leave due to Milhouse not being on the bus, when Otto replies you can see that his left arm up to the headphone cable flashes pink for a frame. (00:07:45)
The Last Temptation of Homer - S5-E9
Revealing mistake: Just before Homer drives backwards into the trout hatchery, when Homer turns the key it is obvious that it is repeated footage of Marge turning the key because the hand is a lot thinner.
Revealing mistake: After Apu and Manjula go by in horse and cart everyone returns into Moe's. When they walk in they just disappear into a brown wall which is where the inside of Moe's should be seen.
Revealing mistake: When Marge says, "Slow and steady wins the race", her face and body are two different colors.
Revealing mistake: When Lisa is clapping erasers, you can see the alphabet above the board, and part of the A is cut off.
Last Exit to Springfield - S4-E17
Revealing mistake: When we see Lisa singing and playing the guitar for the second time, if you look to the right you can see a blue mark on the building that is behind her (On the middle turquoise stripe). It appears and disappears twice.
Revealing mistake: When Lisa is daydreaming about her failed test, the president of Harvard talks to her. When he says, "Nasty business that zero", his right white sleeve turns the same color as the glass above the door.
Revealing mistake: When Lisa and Hugh go by Taxi to the Simpsons house, you can see that they pass the same buildings all the time, especially "Coffee shop".
Revealing mistake: In the scene where Marge is cutting Grampa's hair, his left cheek in the mirror's reflection turns blue.
Revealing mistake: When Moe and Barney are seen drinking wine at the wedding, somebody walks away with a tray. When they are drinking the animation is repeated because you can see part of the tray keeps coming on and off-screen. (Look by the bottom right). (00:13:25)
Revealing mistake: When the announcer says that the Falcons win, he says "Who would've thunk it" Homer says "My daughter, that's who". When he is saying this, Lisa's arm disappears twice. (00:10:05)
E-I-E-I-(Annoyed Grunt) - S11-E5
Revealing mistake: After Lisa says "For a product that's evil and deadly" while standing in front of the tomacco stand, there's a duplicate Lisa behind her that stands still while she moves, giving Lisa the appearance of having two heads. It looks like the animators made a mistake while trying to animate Lisa.
I'm Goin' to Praiseland - S12-E19
Revealing mistake: In one of the scenes (I think it is when they first discover the alleged 'miracle') you can see people in the background walking out of the park. But they are not walking out of the park at all, they are walking into the wall.
Springfield Connection - S6-E23
Revealing mistake: Just after when Marge is reading the book on the sofa she says 'chaos'. On the far left of the screen a large black 'scratch' appears then just slides off.
Suggested correction: I don't see the mistake; I even watched the DVD version, and in the Disney+ version, I don't see it.
Revealing mistake: When the riot police are running into the concert, you can see a 'cardboard' police officer leaning against his car, doing absolutly nothing, not even blinking or talking into his police microphone. (00:07:45)
Revealing mistake: By the end, when fortune teller lays "The Fiance" card on the table, it instantly makes the same angle as other cards lying there, even though the teller's hand is still under it. It doesn't change the angle when she removes her hand from under it, as though it's floating in the mid-air all the time.
Revealing mistake: After Bart gets promoted to Hall Monitor, when he tells the girl at the fountain to keep the line moving, the kid behind her drinks from the fountain but the water does not go into his mouth. (00:13:40)
Homer Badman - S6-E9
Revealing mistake: In the scene where Marge's coat pocket bursts open, the candy flows onto the floor. However if you look to the right of her some of the candy seems to almost float above the floor. The candy's direction is completely to the right but because of the floor being angled it spreads over one woman who is standing and there is nothing there to support the candy. (00:04:30)
