Audio problem: In the scene where Mark Antony and his men are attacked by a mob on their way to the senate forum, Mark Antony says, "Rally to me" three times. The first time he says it, his lips do not move. The third time he says it, the movement of his lips do not match the words.
Audio problem: In the shot where Randy throws the glass of beer at the wall behind him in the Crab Shack, his mother's mouth is not synced with the audio that she is speaking: the audio was continued from another shot, and in this one, she is saying different words. (00:12:00)
Audio problem: When the Vietnamese man is playing Russian Roulette in the end, a few seconds after picking up the gun, he moves his thumb and we hear the gun cock. However, you can see that he didn't actually cock the gun, as his thumb never came into contact with the hammer while moving, hence the sound was a phantom sound.