Revealing mistake: After the detectives bust the cops while Undercover, Alex Cabot enters the interrogation room with Lorna Frankel. Shortly after, someone holding a white box is coming into view just outside the doorway. Benson is waiting for her cue to enter the room.
Revealing mistake: After M.E. Warner tells Fin and Munch the boy was smothered to death, you can see the foot of the "dead body" twitch or move.
Birthright - S6-E1
Revealing mistake: When Munch is driving after the perpetrator you can see the dent in the side of the car moments before he actually hits the car and goes over the bonnet.
Revealing mistake: Near the end of the show where Liv elbows Stuckey you see a stunt double, then when he falls in a split second he's replaced with a dummy.
Revealing mistake: When Amanda and Fin are in Atlanta following up on their rape case, they walk past several cars with visible Georgia license plates mounted on the front. Georgia is a rear plate-only state and wouldn't have had license plates mounted on the front of the cars, as shown here. (00:13:30 - 00:16:20)