Other mistake: The amount of gunk that come from Bart's model at the start is not proportionate to the size of the model. In other words, there couldn't be enough gunk to cover the entire inside of the bus.
Marge Simpson in 'Screaming Yellow Honkers' - S10-E15
Deliberate mistake: When Marge goes offroading to get home there is a grassy field which leads right up into the Simpson driveway. However, in all other episodes there is no grassy field and instead there is a house in the spot where the field would be.
Marge Simpson in 'Screaming Yellow Honkers' - S10-E15
Continuity mistake: After Marge pulls out of the Store, she gets stuck at a traffic jam. But when she does pull up, all of the groceries in the back have disappeared.
Marge Simpson in 'Screaming Yellow Honkers' - S10-E15
Continuity mistake: When Eddie the cop (as Curtis E. Bear) is being bludgeoned with 2x4's at traffic school, Krusty's nose is the same color as his skin instead of being red.
Other mistake: When Homer returns home, Marge says his car is blocking the traffic. But there is some space on the road where his car isn't. The traffic could easily have driven through the empty space. (00:02:30)
Other mistake: When Marge takes Homer back inside, his car is seen blocking the traffic. But at least one side of the traffic is driving on the wrong side of the road. The drivers behind Homer's car are on the right side of the road. And the drivers behind Homer's car from the opposite direction are driving on the left side but facing the drivers behind Homer's car on the other side. Either way, one half of the traffic are driving on the wrong side of the road. (00:02:35)
Continuity mistake: When Homer has the Bill Of Rights, he ends up ripping several parts of it. The rips keep alternating between shots. (00:05:25)
Revealing mistake: When Lisa hugs Homer, there's a person next to her with a missing head. (00:21:43)
Continuity mistake: After Homer falls asleep at the wheel the truck starts to turn the corner. As its going around the bend you can see a white line on the road. The following shot the line has disappeared.
Continuity mistake: When Lisa finds the doorbell Marge wanted and she plays it, it is gold, but when Marge picks it up it is grey-ish.
Continuity mistake: When Red has finished the steak, he lies back and is the same position for Homer's small speech. However, as soon as Homer starts to say 'Wait, you're not breathing,' Red blinks when he is meant to be dead.
Audio problem: When the radio is playing "Wannabe", the song stops but Homer doesn't touch the radio.
Simpsons Bible Stories - S10-E18
Other mistake: Rev. Lovejoy is reading Genesis, the first book of the bible, but he is a good way into the book. Surely it would be at The Front?
Simpsons Bible Stories - S10-E18
Continuity mistake: Homer as Solomon cuts the pie into a roughly 1/3 and a 2/3 piece, but when he picks the pieces up, it's more or less halved.
Simpsons Bible Stories - S10-E18
Plot hole: Somehow, despite being enslaved and being nowhere near anything that could help them, the Jews have a camel, which we did not see coming across the channel.
Simpsons Bible Stories - S10-E18
Continuity mistake: When Bart is trying to wake up Homer, Maggie is seen with a blue pacifier. In the shot after the next, Maggie's pacifier is red.
The Old Man and the C Student - S10-E20
Continuity mistake: Springy the Olympic spring that Homer makes has 9 coils. Then we see the large version that has many coils, at the Olympics meeting. Homer's original spring is in his hand and now it has many coils also. When it cuts back to the stage, the large spring has few coils, like the very first time we saw Springy.
The Old Man and the C Student - S10-E20
Continuity mistake: The springs on Homer's hat change size when Agnes answers the door to him.
The Old Man and the C Student - S10-E20
Continuity mistake: When Homer offers Lenny some nuts a spring pops out and gets Lenny in the left eye, but the next time we see Lenny it is in his right eye.
The Old Man and the C Student - S10-E20
Audio problem: At the choir at the start, Lisa's lips don't move when she says "oh no."
Answer: I'm not sure if this is the one you're thinking of, but an episode of "Ray Bradbury Theatre," called "A Sound of Thunder," dealt with a similar matter: a group of hunters travel back in time to hunt dinosaurs, only to find things have changed when they get back because someone stepped on a butterfly.
Xofer