Deliberate mistake: The shot of Willy running away from the parked car is taken from the episode where Elias is killed. Two things give this away - 1) Willy is wearing a different coloured jacket and 2) he is supposed to be seriously injured yet he sprints along the street.
Continuity mistake: When Charles reads the message about Nathan Bates coming out of the coma, there are two things to look for during the closeup of the note. The logo on the top is replaced by writing and he grips the note in a different position from before. The writing changes yet again when the note is seen from behind.