My one is Terminator the original. I get that the machines they can create a machine, i’ll even given them for creating human blood but one thing that bothered the shit out of me. Is they can probably read and write different languages but how in the hell or why do you make a robot have a german accent?
My head canon for this is that someone inside kept him in the system because they trusted him, such as the Precog technician or the warden.
The realistic answer is that incompetence and red tape delayed removing his credentials when they should have been.
That was also my first thought when I watched it. I don’t remember if they acknowledged it in any way though. In any case neither scenario is that unrealistic.