Audio problem: During the opening credits no one moves their mouth when they notice Superman and say "it's a bird...it's a plane..."
Adventures of Superman (1952)
1 audio problem in show generally - chronological order
Starring: George Reeves, Bill Kennedy, Jack Larson, John Hamilton
Revealing mistake: When the robot releases the balloon with the bomb attached, the wires used to pull the balloon up are visible as the balloon rises through the skylight.
Lois Lane: Eureka.