Homer's Triple Bypass - S4-E11
Continuity mistake: Homer is interrupted from praying by a nurse who comes into his room and says, "Ssh." However, when she says this, the door is closed, and it is only in the next shot where the door is open immediately and she is pointing to the NO PRAYING sign. (00:14:20)
Other mistake: In the scene where the Simpsons are viewing the path of the Corvair's Re-entry, the blip representing the spaceship crosses the entire US from North-West to South-East in about three seconds. This is really impossible, even for something going as fast as a spaceship on re-entry would be.
Continuity mistake: In the beginning, at the hospital, Maggie's bow changes from red to blue when Marge says "Why are you doing that?"
Much Apu About Nothing - S7-E23
Continuity mistake: Willy jumps in and shakes his fists at the children and Skinner who are in a circle around him. Uta has now disappeared from the circle and cannot be seen anywhere when he was there just seconds before.
Much Apu About Nothing - S7-E23
Continuity mistake: When Kearney buys the beer, the shot of the ice cream sandwiches melting in his arm pits shows that the 'Duff' writing on the crate of beer is thinner than previously seen.
Continuity mistake: When Marge and Homer are arguing about Don Quixote, Marge's pillow disappears from under her head. (00:09:50)
Other mistake: In the shot before Marge says she will marry Homer, the right side of the screen is cut off a little. (00:08:25)
Burns Verkaufen der Kraftwerk - S3-E11
Continuity mistake: At the Tavern, when Homer slaps the money on the table, the white cloth that Moe was holding has vanished. (00:04:55)
Continuity mistake: If you watch carefully, the same footage of Bart and Skinner slamming locker doors is used. The easiest to spot is the shots of the camera at Bart from inside a locker, where a kid's scrapbook is on the left side. (00:19:45)
Continuity mistake: When the Stonecutters are singing "We do", the position of several characters, particularly Number 51 and Chief Wiggum, change randomly as the camera angles change. Number 51 starts at the end of the table on the right side, with Chief Wiggum two seats to the left of him. In later shots, Number 51, then Wiggum are both switched to the same position, midway up the left side. Then, when the song ends, Wiggum has disappeared, and Number 51 remains in this new position.
Homer Badman - S6-E9
Audio problem: When Bart and Lisa hug the T.V and Homer asks them if they are, they respond with "No". However, Lisa's mouth moves but you hear no sound.
Continuity mistake: After Kirk (Milhouse's dad) drives away from the stadium, Bart and Homer are walking along and you can see the Drink Duff sign right next to the edge of the fence. The next shot of Homer noticing the sign, the sign is further away from the edge of the fence and is smaller.
Continuity mistake: Just after Bart has played the guitar in the street, he picks up two books. Before Bart picks them up they are green but they instantly turn blue when he does pick them up. Then when he gets on the bus the books have disappeared completely. (00:10:10)
Homer's Triple Bypass - S4-E11
Other mistake: In the beginning of the episode when Chief Wiggum orders a battering ram through The Front door of a house, Reverend Lovejoy opens the door and questions what they are doing. Chief Wiggum says "isn't this 742 Evergreen Terrace?" to which Lovejoy replies that it's the house next door. In the next shot, you see Snake pulling out of the garage and speeding away. Everybody knows that 742 Evergreen Terrace is, in fact, the Simpson residence. (00:02:40)
Tree House of Horror VI - S7-E6
Continuity mistake: In the 'Nightmare on Evergreen Terrace' segment, in Martin's dream, Willie emerges from the blackboard with a rake which has a wooden handle. When the shot changes the rake handle has changed to being metal. (00:08:25)
Children of a Lesser Clod - S12-E20
Continuity mistake: When Bart and Lisa are trying to win back Homer's affection they are sitting on the top of the stairs and push the skateboard with the present on it down the stairs. In the next shot it rolls into Homer's legs yet it would be impossible as he was standing in the main living room which is to the right of the stairs. Pushing the present down the stairs it would go straight into The Front door.
Milhouse Doesn't Live Here Anymore - S15-E12
Continuity mistake: When Homer pulls up at the traffic lights, he stops over both of the lines indicating the crossing. When the woman gives him money in the next shot, he is behind the lines.
Tree House of Horror X - S11-E4
Continuity mistake: In "Desperately Xeeking Xena", as Lucy Lawless grabs the lips of the Collector, you can see a big "C" on the back of his cape. After she has thrown him across the room and he gets up, the "C" is gone. It reappears later in the fight.
Tree House of Horror VII - S8-E1
Continuity mistake: In 'The Genesis Tub', Principal Skinner takes the lid off of the tub, and puts it on the table. In the next shot it's gone. (00:17:55)