When Hank Dick (Darren McGavin) takes the hot dog from Joey Turks (Billy Zane), it has a bite taken off of one end, even though Joey has not yet taken a bite (and the fact that it has a bite off one end appears to be deliberately concealed by the wrapper and its handling, but becomes apparent as soon as Hank picks it up). Hank then takes a bite off the other end, so that it has a bite taken off of both ends. In the next shot, Hank is holding a complete hot dog that has had no bites taken off of it. In the next shot, Hank is holding a hot dog with a bite off of only one end and he is chewing that bite. These shots appear to have been placed out of sequence in the film.
When Bart is sitting in his car outside the diner and shoots Joey's friend through the window, Mona pushes the gun up and away and it goes off after it's pointed upward toward the sky. So, the shot couldn't have gone where it was initially aimed into the diner.