Audio problem: When Matt Groening is putting boxes of comic books into the Comics Bongo Group truck, he says "I'm so rich" but his mouth isn't moving. (00:04:40)
Audio problem: When Homer says "I need change for a dollar. I also need a dollar", his mouth doesn't match what he's saying. (00:07:25)
Continuity mistake: Ms. Krabapple takes the cellular devices from the children in her class and puts them in a Laramie Cigarette box. She dumps the box into a desk drawer filled with frogs. A few seconds later there is a shot of the class from her point of view with all of their cellular devices on their desks. (00:03:00 - 00:08:15)
Continuity mistake: The size of the smiley face on Krabappel's mug keeps changing between shots. (00:04:50)
Continuity mistake: While Edna is holding the "Goddess Bar", her shirt sleeves are pink like her pyjamas, but in the next shot, she is wearing her usual green outfit.
Continuity mistake: Barney is simultaneously seen at the wrestling stadium watching the fight, and at Moe's.
Rednecks and Broomsticks - S21-E7
Continuity mistake: When the Simpsons are on the highway, Apu's car is seen, and some of the octuplets have yellow skin and blonde hair.
Continuity mistake: When Carl and Lenny are lowering Homer onto the train window, Lenny's five o'clock shadow is missing.
Once Upon a Time in Springfield - S21-E10
Continuity mistake: The merchandise Krusty asks the kids to hand back doesn't appear in the kids' hands until the merchandise is taken off them. (00:01:55)
Once Upon a Time in Springfield - S21-E10
Continuity mistake: Mr. Burns shows a box of doughnuts coloured pink, brown and light brown. When the guys grab them they're all pink.
Million Dollar Maybe - S21-E11
Continuity mistake: When the bulls are stampeding, people who were at the top of the stadium and safe can be seen running in front of the bulls.
Continuity mistake: When Mr. Burns is confronting Homer about his missing slave, Homer's donut is half eaten. During the next scene the donut has a smaller bite taken out of it. (00:14:00)
Factual error: In the scene where Lisa's great great grandmother, and the slave Virgil escape to Canada, they enter Canada across a suspension bridge, which has, on the Canadian side, the Canadian Maple Leaf flag. In 1860, Canada was not yet even a country, and the flag was the Union Jack and the Canadian Ensign. The Maple Leaf was not adopted as the Canadian flag until February 15, 1965.
Postcards from the Wedge - S21-E14
Continuity mistake: When Lisa is talking to Bart in her room, Lisa's necklace is red rather than white when Bart shouts "End all life on this planet!" (00:08:05)
Continuity mistake: When Scratchy's head gets sucked into the dam pipe, the back of his head goes in first, but when he is shot out, he is facing forward.
American History X-cellent - S21-E17
Continuity mistake: When Homer, Carl and Lenny are drinking at Moe's Tavern, Smithers' bottle in front of them on the table changes position between shots.
American History X-cellent - S21-E17
Continuity mistake: When Smithers walks up the desk in his office, there is a box of items in The Front of his desk. But when he is looking at a portrait of Mr Burns, the box is now on the side of the desk.
American History X-cellent - S21-E17
Continuity mistake: When Marge is speaking to Bart, Homer comes out of the house with a pumpkin and you can see there is nothing on the doorstep. But when Marge goes to the car, a green doormat has suddenly appeared, and when she leaves, it has gone again.
American History X-cellent - S21-E17
Continuity mistake: When the policeman is speaking to Mr Burns about the stolen artwork, the molding on the door behind Mr Burns changes between shots.
