Audio problem: In the scene where Freddy cuts off a doll's head to replace Wondermut's old toy Bob, there is a close-up of the doll head being shaken with Freddy's head visible in the background. You hear Freddy saying, "Look Wondermut. I found Bob," but you can see that Freddie's lips aren't moving.
Audio problem: As Pruitt is beating up the adulterer in the street, despite the sound effects, it's obvious that his punches are missing. (00:27:35)
Audio problem: After the "Off to See the World" part, it shows Klaus and Claudia in the pool. The waiter tells Claudia that there's a long distance phone call for her from Europe. "Wonderful!" Claudia says, and she slides off her raft and while she makes her way out of the pool, accidentally drops water on Sophie. The dog freaks out, trying to paw the water off her and Klaus snickers at her. After the shot of snickering Klaus, it shows Sophie turning her head towards Claudia and you could hear her bark. However, she does not move her mouth as if she's barking and the barking noise sounds quite perky.
Audio problem: The keyboard Kevin gets from the music shop seems to have an interesting trait, in that the high notes are on the left. This must either be bad "audio dubbing" or something to do with the shot perhaps being reversed, although I doubt this. It's most likely a post-production audio error as very very few keyboards or pianos are configured in this way.
Audio problem: The radar operator (making the sounds of a garbled intercom) is laughing through his next line "I'm having trouble with the radar, Sir." (After/when Dark Helmet throws the intercom across the control panel). (00:21:45)
Audio problem: In the mansion, the boys open a secret passage and fall through the floor. They scream after shining a flashlight on a skeleton. Eugene then can be heard whining that he wants to go home, but his mouth is not moving.
Audio problem: It's quite obvious that all of the grunts and sounds of terror that Ash makes while his hand is attacking him in the kitchen are dubbed. (00:28:45)
Audio problem: At the wedding, Nadia sees Walter across the pool and in the close-up of her face we hear her let out a loud shriek, but visually she does no such thing. (01:29:55)
Audio problem: When the biker shows up at the end, Holly Hunter asks Cage what he is, to which Cage replies "Do you see it too?" but his mouth is not in sync with what he is saying.
Audio problem: When Lord Crumb says "Once the Fast Food authorities have checked the samples..." his mouth movements are way out of sync with the audio. (00:45:50)
Audio problem: When Axel is in the shed in the final shoot-out with Dent and Karla, there is a flopping sound from the ceiling fan. The instant Karla gets shot, the sound disappears.
Audio problem: After the ninja fight, Lassard knocks down a ninja hitting him with his baton, but no noise is heard, making it a really lame and fake hit.
Audio problem: After the incident in the flight chamber with Goliath at the film's climax, Jimmy turns to Teri and says "let's get the hell out of here." However, the audio does not his mouth movement, as he was saying "let's get the fuck out of here." (01:31:40)
Audio problem: As Neil is talking to his coworker about getting on a plane, the audio is either different or synced wrong, as the coworker says something different. In the shot facing Neil his mouth doesn't match.
Audio problem: When the hotel owner is showing the Lambdas around the grounds, she says, "Over here is our beautiful Olympic-sized pool." The word "beautiful" is cut off. Poor editing.