Audio problem: After the part where Johnny Depp finds his bookstore friend dead, he gets back in the cab. After driving for a while, he tells the cab driver to pull over to the phone booth. The cab driver says "No problem, sir" but you can see the cab driver's lips in the rear view mirror, and they never move.
Audio problem: While Depp is at 'P y P Ceniza Restauracion De Libros', one of the bookstore owners (man on right side of frame wearing blue apron) says, "I would never have believed she'd parted with it, never." He obviously did not say this. He actually appears to either ask his brother a question or make an entirely different statement. (00:38:30)
Audio problem: In the very first scene where we see Corso, in the high class apartment, giving his false estimate to the yuppies. He walks over to the disabled man in the wheelchair, and as he turns from the window he says "I understand." But upon closer inspection, his lips never move.