Revealing mistake: The re-use of a brief scene from the pilot episode, inserted during Nick and LaCroix's vampire battle in the warehouse, creates the unfortunate problem of Nick completely changing clothes in the middle of the fight. (00:37:35)
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)
Heart of Ice - S1-E3
Revealing mistake: When Batman - disguised as a security guard - opens his utility belt, the belt opens and shows a configuration of buttons and a split-second later, a key card materializes out of thin air in front of the buttons. (00:11:30)
Revealing mistake: When Roberta Halton knocks Rob unconscious, you can see that the blunt object barely even makes contact with his head.