Continuity mistake: It is stated multiple times that forensics reports showed that the Bay Harbor Butcher used ketamine to incapacitate his victims. However, it wasn't ketamine that Dexter used in the original series, but rather M99.
Never Meet Your Heroes - S1-E1
Continuity mistake: The little girl is barefoot in the opening scenes but when her feet are reflected on the oven door she has white socks on.
Episode #1.7 - S1-E7
Continuity mistake: Monique is making "tea" for Stephanie. She is stirring the drink and suddenly the glass is way more empty. (00:25:13)
Continuity mistake: Alina is trying to escape both the Crows and General Kirigan's men through the streets of the town of Ryevost. While in an alleyway, she kicks in the door to a building, only to still be outside when she emerges from the other side of the door - when she looks back inside of the door she just emerged from, it leads to the interior of a building, not the alley she just came from.
Episode #1.1 - S1-E1
Continuity mistake: When Mark got into his cell, the top bunk had a vinyl-like covered mattress (or folded gym mat) that had a lengthwise seam along the middle of the side. He was not fixing his bunk bed while he was talking to cellmate Bernard, but when he was removing items from his bag on top of the bunk bed, it was now covered with a blue blanket and a sheet folded down by the pillow could be seen. A little later, the blanket was also covering the foot of the bed. (00:13:15 - 00:15:03)