Audio problem: When Lionel tells the others to lift the button at the center of the compass, you can notice that the music box is still playing, but the drum of the machine is still. (00:08:30)
Audio problem: Katherine visits Poirot at the field hospital; the opening line has a loud gulping, most likely dubbed, and then Branagh's voice says "I asked you...not to come" with the second part of the sentence added in dub; his lips don't move. (00:05:45)
Audio problem: The baddie enters the room with the two ladies and fires a shot in the air. He is holding a revolver but the empty casing can be heard hitting the floor as if the pistol was magazine fed. (00:39:00)