Factual error: There is a "Covered California" sign in a window. The referenced health insurance exchange did not exist during the 1990 time setting of the movie. (00:20:58)
Continuity mistake: In the desert digging, the Nova's trunk is open, then shut. (01:42:00 - 01:45:00)
Deliberate mistake: Denzel Washington never wears a vest (at least during the previews). All deputies are mandated to wear at least a level II vest (most will buy a higher protection vest) whenever performing Sheriff duties. Plus his duty shirt is just plain sloppy looking, way too big for him.