Corrected entry: After Pops is upgraded becoming a T-1000 he should be young as a new model but is still old.
Corrected entry: When John Connor is pulled apart by a magnet, the other layers of the T-3000 are shaped like the evolution of man.
Correction: No, it's not. It's not even close. It's just pieces of John being pulled apart as he struggles to get away from the magnet. The images are essentially the same height and upright. In fact, two middle images are the tallest and straightest.
Corrected entry: Sarah throughout most of the movie wears her hair in a ponytail. In the scene prior to using the time machine her hair is loose because she can't wear any clothing. However her hair is somehow back in its ponytail prior to her stepping into the time machine.
Correction: We don't know how much time passes between these scenes, and none of the shots of her hair down then in a ponytail are continuous shots. After they're done talking about what year to go to, the next scene they're already in the locker room and her hair is down, and she had plenty of time to do it. She could have taken it down for a number of reasons, such as brushing it or because something got in her hair. After that, the next scene is all 3 at the time machine. She could have put it in a ponytail out of habit or because they had more to do, and again, she had plenty of time to do so. She even covers herself after taking her clothes off even though she's going to be naked in front of Kyle, so no reason to think she couldn't put her hair back up in the meantime. Of course, as she enters the time machine and disrobes she takes her scrunchie off to let her hair down.
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.
Factual error: During the opening narration Kyle Reese states that Skynet attacks humanity on August 12, 1997. In the shot of missiles decimating San Francisco, multiple 2005-present Toyota Priuses, Dodge Chargers and other late model cars are seen.
Suggested correction: That 1997 was from another timeline before the events in Terminator 2 altered history. It's possible those models may have existed earlier in that timeline than in our world.
This is assuming too much about the alternate timelines. There would have to be more concrete evidence that such things would be altered in said timelines. Also, considering that timeline is supposed to be what took place from Terminator 1 in its own separate timeline, we would go still by our own following the events of it leading up.
Correction: A T-1000 (or any liquid metal terminator) is capable of changing its outer appearance. It makes sense that Pops would keep his appearance familiar to Sarah so she recognises him and doesn't immediately assume he is a different Terminator out to kill her.