Marge vs. the Monorail - S4-E12
Continuity mistake: Mayor Quimby's suit changes from dark blue to purple throughout the whole town hall scene.
Marge vs. the Monorail - S4-E12
Continuity mistake: Throughout the whole town hall scene, people constantly change positions between shots.
Marge vs. the Monorail - S4-E12
Continuity mistake: When celebrities are coming to ride the monorail, the positions of people in the crowd changes positions between shots.
Marge vs. the Monorail - S4-E12
Continuity mistake: Doctor Hibbert was among the passengers on the monorail on the first ride, but he is seen with a pair of conjoined twins in his office soon after.
Continuity mistake: When Bart and Lisa wake Homer and Marge up in the morning of the Duff Gardens visit, the kids are standing by the bed. However, when Marge throws the mouldy sandwich in the bin in the next shot and Homer collapses, the kids have disappeared. In the next shot, they are back again.
Continuity mistake: When the police talk about the bumper cars getting stolen by Jimbo Jones, you see him and his 2 friends riding off in bumper cars. From the side angle, there are 2 blue and 1 red car, but from the rear view, there is 1 blue, l red, and 1 green car.
Continuity mistake: In this episode Hans Moleman's skin colour is yellow. However in "Duffless " his skin colour is brown and in other episodes it is a dark yellow-green colour.
Continuity mistake: When Selma is on video at the end of the episode, the iguanas's eyes change from yellow to white during the scene, but not between shots.
Brother From the Same Planet - S4-E14
Continuity mistake: After Pepi and Tom walk off into the sunset together it cuts to Bart handing Homer another beer, and the picture behind the couch has brown sails over the boat, but next shot it's colored properly with white sails. (00:21:30)
Brother From the Same Planet - S4-E14
Continuity mistake: When Homer is showing Pepi the garage, it is purple. In the main titles and in every other episode, it is an orangey colour.
I Love Lisa - S4-E15
Continuity mistake: When Homer and Bart are watching a clip of Sideshow Mel on wowee sauce and Bart then says "I'd give anything to go to that show", he has nothing in his hand. The shot cuts to Homer and he then says "I'd sell my first born son" and then the shot cuts back to Bart. When the shot cuts back to Bart, a Buzz cola can has appeared in his hand out of nowhere. (00:08:20)
Last Exit to Springfield - S4-E17
Continuity mistake: When we see McBain at the beginning of the episode, after shooting some people, the magazine falls out of the machine gun. But from the next shot onwards it is back in the gun.
Last Exit to Springfield - S4-E17
Continuity mistake: When Mr Burns is telling Homer to resign, he has glasses on in the first shot in the scene. However his glasses are on his desk the next shot onwards.
Last Exit to Springfield - S4-E17
Continuity mistake: When the dentist shows Ralph the Big Book of British Smiles, he first shows him a picture of Sherlock Holmes with horrid teeth and all of his teeth are there. When Ralph starts getting terrified of it, it shows the same picture, but this time one of his teeth on the bottom right hand corner of his mouth is missing.
Continuity mistake: During the Itchy and Scratchy episode at the beginning, Itchy's hammer changes from being held above him to beside him between shots.
Continuity mistake: When Roger Meyers throws his nameplate at the writer the second time, the animation is repeated from when he threw it at him earlier. It's more obvious because his mouth doesn't match what he's saying and the background is orange instead of purple like the rest of the scene.
Continuity mistake: Millhouse is in the classroom at the beginning when Principal Skinner says that superintendent Chalmers is coming for a surprise inspection, but when they show Nelson he is getting crud put down his shirt. How could he be at two places at once?
Continuity mistake: On 'Whacking Day,' Homer is seen charging people to park on his lawn. But later when the snakes are lured to the Simpson house, there are no cars there.
