The Great Money Caper - S12-E7
Continuity mistake: When they are driving home Marge starts to moan at the children to quiet down. In this shot she has no lipstick. In the next shot from outside the car she has lipstick on and has it for the rest of the scene.
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