Other mistake: During the bar scene when the T-800 is on the motorcycle and the bar owner comes out and fires the gun, Arnold Schwarzenegger flinches, specifically his eyes close. (00:09:30)
Suggested correction: The shot cuts away from Arnold almost immediately after the gunshot. For the split second that the camera remains on Arnold, the most we can see is maybe a blink, but definitely no visible flinch or reaction to the gunshot that warrants a movie mistake.