Audio problem: Dr. King is looking at the strange situation in front of Emily's tent while Lady Westholme is talking to her. In foreground, Lauren Bacall's lips don't match the audio of what she's saying. (00:44:35)
Audio problem: Hassan runs away, chased by Dr. King. A wild Lady Westholme appears and says a line that does not match her lips. (Peter Ustinov's lips move without a sound as well, but in his case Poirot is self-censoring an expletive). (01:15:15)
Audio problem: Lady Westholme pushes the half-open door against Poirot twice. The door makes the same sound it does when it gets slammed shut later (twice). As stocky as Peter Ustinov is, he's not made of wood, and while obviously a door hitting a person would make a thud (I admit having tested it), it wouldn't make the kind of sound heard here. (00:58:35)
Audio problem: During the fireworks, Poirot's line about the "nice and royal" show giving him "confidence" is dubbed over, and you can in fact see Peter Ustinov in the shot of the crowd, not saying those words. (01:37:40)
Audio problem: When Poirot stands from his seat after telling the truth about the spider, he looks at Dr. King. Her lips move but there is no audio. (01:33:50)
Audio problem: When Carrie Fisher and David Soul make out in Trieste, a performer at the local restaurant is supposed to be singing the popular Italian song "Torna a Surriento", but his lips barely even move and it's self-evident that he's not the one singing. (00:11:30)