Audio problem: The Philip Morris bellboy in Jack Rabbit Slim's does the famous "Call for Philip Morris." while walking away from the camera. When he turns to the side and does the call again, we can see that his mouth movement doesn't match the vocal.
Audio problem: After reviving Mia with an adrenaline shot, Vincent collapses onto the carpet. We can hear him say, "Oh man" but his lips are actually forming different words. (01:00:55)
Chosen answer: Tarantino is big on tribute to older films and filming techniques, hence the projection-style background.
Captain Defenestrator