Mistaken Identity: Part 2 - S9-E2
Revealing mistake: Near the end when Frost calls Pam to warn her about Meadows, she walks in to the hall and picks up the cordless phone. After she's looked out of the window and seen the killer staring at her, she 'does a Kim Bauer' and holds the phone upside down while she continues speaking with Frost. (02:09:00 - 02:10:20)
Revealing mistake: When the Blue car is after the fake pizza boy there are three shots of the car being driven by a man and not the woman who a few seconds ago was driving.
Near Death Experience - S12-E1
Revealing mistake: At the end Jack wrestles the knife out of the attacker's hand and in doing so cuts his own hand. However in the extreme close up you can see the rubber knife is bending when Jack wrestles it away. (01:30:30)