Deliberate mistake: Near the beginning, there is a shootout between Nick and Earl and a man is filming it. The version of events on the tape shot by the man and the real version we saw prior are different. Lithgow has an extra line, as does Washington.
Deliberate mistake: When Lithgow is shot in the leg and trips backwards over the crate or box, the stunt man is deliberately visible. It's not Lithgow making the fall.