Radio Bart - S3-E13
Audio problem: When Homer talks to Marge about Bart's present, the same footage was taken from 'Saturdays of Thunder,' because you can see that Homer's mouth doesn't move right. (00:02:40)
Radio Bart - S3-E13
Audio problem: Just after Krusty kicks Sideshow Mel into the big birthday cake on his show, he says "Hey kids" but his mouth doesn't move right.
Answer: Willy referred to an encounter he believed he had with actual aliens, while Wiggum thought he was referring to the arcade game.