Children of a Lesser Clod - S12-E20
Continuity mistake: When Ned Flanders is asking Homer whether or not he is running a daycare centre, there is a radio behind him. The aerial on it changes position in subsequent shots.
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.
Children of a Lesser Clod - S12-E20
Audio problem: When the moon says, "You go, Homer,'" the words dont match what the moon says.
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