Other mistake: As Chief Wiggum is being interviewed about the fugitive, his arm is shown to be in a cast due to the police van crashing at the Krusty Burger Drive-Thru earlier on. Yet when they get to the hospital, his arm is completely fine. (00:17:30 - 00:19:00)
Other mistake: At the end of the episode Lisa and Bart watch Itchy and Scratchy in the TV room, which is beside the kitchen at the back of their house. The TV room has a window that faces the backyard, with the record player on a shelf in front of that window. The problem is when Bart looks out the back window and sees Lester skateboarding past the house, the view outside is actually the street in front of the Simpson house, not their backyard as it should be.