Miles to Go - S6-E15
Continuity mistake: In this episode Rose's boyfriend Miles is revealed to be in the witness protection program and has not had any contact with people from his past including family. However, in season 5, episode 15 his daughter visited and didn't approve of Rose.
In God We Strongly Suspect - S2-E13
Continuity mistake: When David and Maddie are in the mortuary and David is rambling about birthdays, he licks birthday cake icing off his finger and removes said finger from his mouth. In the next shot, the finger is back in his mouth.
Continuity mistake: Mike's hair keeps changing throughout the episode.