Audio problem: The scene where Bennet and Matrix are fighting towards the end of the movie, before Matrix kills Bennet they have each others throat in their hands and one of their backs is against the furnace. While they are grunting and groaning, if you listen carefully, you can hear one of them say "switch" just before they change positions. (01:19:05)
Audio problem: Lorraine comes to see Marty in Doc's garage in 1955 to ask him if he will go to the dance with her. Just before Lorraine moves to the other side of the car from where she walked in, she begins to say something to Marty. The problem is that her lips don't move when she talks, I guess the right clip ended up on the editing room floor. (01:11:40)
Audio problem: When the policemen are beating Kersey in the interrogation room, the words that they are saying do not at all match their mouths.
Audio problem: At the end of the movie, after Manny has disconnected the locomotive from the rest of the train which is slowing down, when it stops we can hear it screech. It shouldn't as the train slows down naturally without the help of the breaks, which additionally, as it had been mentioned (by the woman), are not working. (01:45:30)