Revealing mistake: In the scene where Rigby returns to the office and finds 15 messages on her answering machine, the second message is addressed to the name of the actor (Meaghan) rather than the character.
Other mistake: Curtis grabs Alisha's hand without activating her power. (00:16:45)
Episode #1.4 - S1-E4
Continuity mistake: Mr. Knightley has just confessed his love for Emma. She is about to kiss him and is holding his face with both of her hands. Her left index finger moves from being right on his ear to being behind it and further down on top of his hair. (00:48:40)