Continuity mistake: When the T-1000 walks past the deactivated T-800 just after being shot at by Kyle Reese, you can see that the T-800 has taken a lot of damage to the face and the nose is missing. Once the T-800 gets up after being reactivated you can see that the nose is back with a lot less damage to the face with a close up shot.
Continuity mistake: In the bus scene on the Golden Gate bridge, right after the bus flips end-over-end, we see it sliding broadside from Pops' point of view through the hole in the police car windshield, at most a few hundred feet ahead. At this point, the bus falls over the side of the bridge, breaks apart, then catches and hangs there. In the ensuing wide angle shot, even though Pops was a mere block away and racing at top speed, his car is nowhere in sight. What's taking him so long? Did he take the scenic route? Perhaps stop for beverages? Meanwhile, as Kyle and Sara snap out of it, exchange some dialogue, and begin scrambling upward to safety with John Connor again in hot pursuit, a full minute passes before Pops finally rolls in to save the day. (01:28:35 - 01:29:15)
Continuity mistake: When Pops, Kyle and Sarah are in the helicopter, Sarah's hair flips between loose and tied up in a ponytail.
Continuity mistake: After the truck crashes into the fire hydrant, Kyle picks up the gun and searches the back to shoot Pops. He appears around the back and aims the gun, with the gun raised to his chin. The shot then cuts to a closer shot of Kyle, with the gun now suddenly lowered to his chest. (00:28:50)
Continuity mistake: After Pops puts the deactivated T-101 in the truck, the mouth is closed in typical grim determination type look. A few minutes later, the expression has changed somewhat and the mouth is slightly agape. Later, in the factory, the 101 is laid on the floor, and the face is in the original position of determination.
Continuity mistake: Towards the end while Kyle is talking with his younger self, the sun changes between shots.
Continuity mistake: When the T-1000 is coming after Kyle, Sarah and Pops in the van, they shoot at his police car. In one angle the bullets break through the glass. In the next shot from the T-1000's view, the bullet holes are gone. They then return.
Continuity mistake: When Kyle is introduced to Pops in the truck, the scenery outside doesn't match the street when the T-1000 picks up its small piece.
Continuity mistake: John has the scars on his face from Terminator Salvation events indicating that it's the same and original timeline, and also Skynet was going to send the T-800 to 1984, but the original T-800 is sent once again in Genisys.
Suggested correction: Terminator Salvation and Terminator Genisys are not in the same continuity. The scars on John Connor's face have been a recurring feature since he was shown in Terminator 2 (played by Michael Edwards). Both Salvation and Genisys were referencing this original design of the character.
Continuity mistake: The wounds on Kyle's and John's foreheads disappears before they send Kyle to 1984.