Continuity mistake: All shots of the Jeep Cherokee prior to it crashing (and during the process of flipping over) show that it wears factory-optional silver steel wheels of a 'star' style. But as the wreck settles upside-down, it's wearing plain steel wheels (like those found under full wheel covers or on a spare tire).
Continuity mistake: Season 2, Episode 18: "Today Is The Day, Part 1" - At the beginning of the episode, Jesse hasn't gotten rid of Riley's body yet but has somehow found the time to replace her living room table which was broken in the previous episode, "Ourselves Alone", whilst fighting with Riley.
Continuity mistake: Season 2, Episode 5: "Goodbye To All That" - We see Marty Bedell playing on his Xbox 360 with a headset attached to his right ear. But when the T-888 arrives at his house to kill him and he goes to answer the door, the headset is gone. There was absolutely no time for Marty to remove the headset as the camera cuts too quickly.
Revealing mistake: When Connor and Cameron are trying to save Derek Reese from the police truck, Cameron walks on the Jeep's hood to jump onto the police truck. During her walk, we can see that it isn't Cameron but a stunt double. She doesn't look like Cameron and is a bit taller. (00:33:05)
Continuity mistake: When John and Pyle are at the shooting range, John's protective glasses are up on his head when he fixes Pyle's gun, down on his face when he fires the gun, back up on his head after firing and then back down on his face when he gives the gun back to Pyle. They're then back on his head before taking them off before the scene ends. (00:13:45)
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: When Sarah throws Cameron out of the window after the rigged safe deactivates her, she lands on the roof of a car at the bottom with her legs straight, arms straight at a diagonal angle and her head looking straight up. But four shots later, she is lying on the car with her legs bent over the roof, her arms at a horizontal angle and her head looking to the left.
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.
Continuity mistake: Throughout most of the episode, the repeated conversations seen in each character's stories are slightly different to each other: the way certain lines are delivered, the position of the actors, etc. These scenes were most likely re-filmed.
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.
Visible crew/equipment: When John gets back from seeing Riley's body, he sits down at the kitchen table in front of Sarah. Sarah tells him he shouldn't have gone. John then says, "It was a risk, I know". As he says this, the shadow of a boom mic can be seen on the wall behind him.
Continuity mistake: After Sarah lies to get Cameron away from the cop, the collar on Cameron's jacket is folded forwards over her neck as she walks down the alley with Sarah. She then tells Sarah that it's 13 miles to walk home and that they need another car. In the following shot, her collar is folded back towards her shoulders.
Continuity mistake: In the scene where Derek shows John his past self playing baseball with Kyle Reese, Derek hits the ball towards John, John picks it up and then gives it to Kyle. As Derek hits the ball towards John, he is holding the bat at an upwards angle towards the right. But in the next shot of him, he is holding the bat at a downwards angle towards the left. The ball also travels in the opposite direction to what it did previously.
Revealing mistake: In Cameron's Story, in the scene with her and Derek, Derek's phone rings. When he looks at the screen it shows a telephone number and the words "EDIT" and "BACK" in the bottom corners. The phone is not in fact ringing at all. Derek is merely looking at the details of a contact saved on the phone.