Audio problem: When the family are about to enter the Knowledgeium Homer says 'Will there be beer?' but his lips don't move.
Audio problem: At the Penitentiary gates when Ralph says 'Daddy's key went in there,' his lips don't move.
Audio problem: When Bart is reading Marge's police file he says 'Oh, Mum's only been in twice.' But the lip sync is a bit out because it does not match the words he says.
Answer: Willy referred to an encounter he believed he had with actual aliens, while Wiggum thought he was referring to the arcade game.