Continuity: Season 7 Episode 7 "Mother's Little Helper" When Kitty is showing Red "The Joy Of Sex" in the kitchen, the book goes from open to shut instantly between shots.

Deliberate "mistake": In the beginning of the episode where Bob and Red are competing with their Veteran's Day barbeques, Red is seen wearing the uniform of a Chief Boatswains Mate (BMC). However in a later episode where Kitty and Red are trying to remember how they met, in a flashback, Red is seen wearing the uniform of a Machinist Mate 2nd Class (MM2). Surely he advanced in rank, but I doubt he changed rates (jobs).