Revealing mistake: When Harvey Bullock and Jim Gordon enter the apartment of the arsonists, as Bullock approaches the bodies, you can see one of the actor's eyes close, despite the fact he is supposed to dead. (00:20:10)
Revealing mistake: In the forensics lab Carol Wilson is saying to others that the rat caught on the ship is healthy. In the ensuing conversation the respirators they are wearing are so ill fitting as to be pointless - Carol's mask does not even touch her nose. (00:26:00 - 00:27:00)
Episode #9.2 - S9-E2
Revealing mistake: Rose's newborn baby, Isabel, is suspiciously large and mature.