Revealing mistake: When Kyle gets to the past and hits the floor his body changes - even his hair and the sweat on it, showing the stuntman.
Revealing mistake: Just before the tanker blows up near the end, there is a scene of it turning to hit a vehicle. The cable pulling the truck is visible.
Revealing mistake: When the inner workings of the T-800's damaged arm are shown, he uses a vise grip to pull one of the finger control rods. As he does, the finger uncurls a split second before the rod is pushed back.
Chosen answer: Since terminators cannot self-terminate, only one very likely possibility comes to mind: it would have hidden itself away somewhere known to have remained undisturbed in the years between the termination of Sarah Connor and the start of the war, at which point it would rejoin the war effort.
Phixius ★