Deliberate mistake: During the sting attempt towards the beginning, Douglas confronts Snyder on the roof of the building. A helicopter rises up from nowhere without making any sound prior to that.
Deliberate mistake: During the Hall of Fame sequence at the end, Dottie sees the display about Jimmie hitting 58 home runs and there is a long wide shot of it as she stands next to it. Then there is a close-up of the bottom of the text which says born 1906 - died 1987, which wasn't present during the wide shot a moment earlier. The filmmakers likely saved this for the close-up for dramatic effect, but by blocking the initial shot without that part obscured it makes the text magically appear out of nowhere.