When Bitsey Bloom was watching the tape in the motel room before she asks Zack to go re-create the crime scene. A quick short close up of Zack sleeping showed him wearing a watch. Before and after this close up he was not wearing one.
Towards the end of the film, Sharon Gale, David's wife, receives the silver suitcase with the post card from Berlin in it. The postcard was mailed from San Francisco to Texas but has no postmark on it in the upper right hand corner as it should.