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.
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.