Continuity mistake: *Season 2, Episode 21: "Adam Raised a Cain" - When James Ellison leaves the elevator after talking to Catherine Weaver, Catherine's fringe has changed from its original position. At first it was diagonally across her forehead, but when James leaves the elevator, it is swept back.
Continuity mistake: Season 2, Episode 21: "Adam Raised a Cain" - When the water delivery Terminator kills Debbie by shooting her in the head, there is no visible entry wound. But later when Derek finds her body, there is a bullet hole suddenly in the middle of her forehead.
Revealing mistake: Some of the security cameras in the Weaver's household are in some rather odd locations. We see a camera's point of view of Savannah looking up through the glass table that she's doing her homework on, and a camera's point of view of Savannah hiding behind the TV. Besides the obvious need for John Henry to keep an eye on her, what is the need for these cameras? And where are they placed? Later on in the episode, when John Henry is talking to James Ellison about why he stopped looking for Sarah Connor, pretty much all of the cameras on the wall next to them are recycled shots from the actual show and couldn't possibly be from physical cameras due to their awkward angles.