Audio problem: On the bridge, sounds of a nearby boat can be heard; however, a boat is never actually seen nearby, nor any lights on the water.
Audio problem: Deckard investigates the maker of artificial reptiles; an Abdul somebody. It's obvious that the dialogue was added as neither actor is in sync with the sound. The end of the scene has the storekeeper's voice telling Deckard the information he was seeking while Deckard's mouth is the one moving. Deckard's mouth continues to move even after Abdul's lines are finished and the scene cuts. This has been corrected in the 2007 Final Cut of the film, but exists in all previous versions. (00:48:45)
Audio problem: When singing Reproduction, a boy sings "Oh I think I'm gonna throw up"; yet he sticks his finger down his throat and keeps it there until the line is over, never closing his mouth; how did he make the 'p' sound on 'up' without closing his lips together? The words are pronounced very clearly and the camera doesn't cut from his face until after the line is done.
Audio problem: When Kirk says, "Stop energizers," watch his lips closely - he really says, "Stop engines." Mike Okuda points this out in the text commentary on the Director's Edition DVD. The reason the line (and also the one following it) was redubbed was because someone pointed out during post-production that the engines couldn't simply be stopped on a dime. (00:39:08)
Audio problem: In the scene where Jack Brown (Richard Pryor) is talking to Eric about "Earning a friend" there is a problem with the lip-sync when the camera changes to an overshoulder of Richard. His mouth is moving but the spoken text is different. This occurs repeatedly during that scene.
Audio problem: When the Stuka 'bombs' the bunker that Pink's father is in, we see it pass overhead, making the unique Stuka 'scream'. Then we hear the whistle of the bomb as it falls to earth, yet we still see the bomb is attached to the underside of the Stuka. The Stuka shown carries just the one bomb, so it isn't another one that is falling. The truth is that this Stuka is a remote-controlled miniature that did not have the ability to release its fake bomb, and the editors failed to avoid using the whistling sound until this shot was over. (00:07:55)
Audio problem: After Spicoli crashes Jefferson's car, Jefferson's brother says "My brother's gonna kill us - he's gonna kill us" yet his mouth isn't moving during those lines (even though shown from the back you can still tell). Then camera faces him and he now matches the words.