Audio problem: When Vince and Mike pull the tabletop out from under the car, while Roy is under there with Mrs. Merkle, we hear the audio of Roy loudly saying, "I'm telling you right now, we're gonna have to brace this thing well, this thing will...," but what's oddly funny is that the dialogue is dubbed right over Roy saying, "Wait, wait, let me check her over...," which is a neat trick that he can say both lines at the same time.
Audio problem: At the end of the show, when Trapper is playing his instrument, the music does not match the movements of his hand.
Goodbye Mrs. Slocombe - S10-E1
Audio problem: At the end when Capt. Peacock comes onto the floor in his maintenance garb, Mr. Harman points him to a spot on the floor and tells him to mop it up. In the initial shot Harman is indeed telling him, but when the camera cuts to another angle Harman is visible and still talking but his lips aren't moving.
The Reunion - S1-E14
Audio problem: When John grabs Olivia from the kitchen sink to rejoin the family (over the washing machine snip) the children's laughter sounds more like a canned echo, or studio audience response.
Audio problem: During the dream sequence, while the spirits of Christmas uses echoing sounds in their voices periodically, Fred's voice was not supposed to echo at all, but his voice can be heard echoing as well a few times.
The Caped Crusader Caper - S1-E15
Audio problem: The Joker says, "It's those tiresome teenagers," but it comes out in The Penguin's voice.