Audio problem: Dr. Marvin watches the magnetic interference unit take down an alien spaceship and says, " saucer hit and down in the Potomac". If you look closely his lips do not match what we hear. (00:13:10)
Audio problem: As Becky and Miles go down the steps after leaving his office. Miles keeps mouthing something after we hear the dialogue stop. (00:07:20)
Audio problem: After the Red Sea parts, and almost all of the Hebrews are across the dry expanse, the pillar of fire holding Pharaoh back disappears, and the chariots head into the expanse themselves to pursue the Hebrews. A very young Hebrew boy at the rear of the masses says 'Look, Grandpa! Pharaoh and his men are coming!' and points at them with his free hand. Watch his mouth: the child is merely moving his lower jaw up and down. Apparently the child actor was too young to learn any lines so the producers improvised.
Audio problem: When the crew are getting into the land rover tractor after the captain chews out his crew for letting the alien onboard, you can hear the "steel" door close with a heavy obvious metallic clang. A few seconds later the same door closes with a soft plywood thud, and a few seconds later it closes with no sound at all as if light as a feather. (00:36:00)
Audio problem: When Foghorn Leghorn says "Something went wrong!" when he is trying to sort out the camera, his beak does not move.
Audio problem: When they arrive in Spain, Passepartout speaks to a Spaniard, whose heavy foreign accent shows he's not Spanish (it was Italian born and USA citizen Constanzo "Jose" Greco). It is so obvious and lame that his Spanish voice was dubbed with a real Andalusian accent in the Spanish release.
Audio problem: Throughout the opening scenes, the innkeeper's lips are out of synch with his dialog due to a less-than-stellar job of overdubbing. The voice substituted for the original actor's belongs to director John Huston. (00:05:00 - 00:13:30)