Continuity mistake: When Poirot in his teatime speech addresses Raymond Boynton, there's a close-up on Dr. Sarah King looking at Poirot defiantly. There's no direct sunlight on her, but then there she is, sitting next to Raymond with sun all over the chest and left shoulder and cheek. (01:19:50)
Continuity mistake: Poirot runs through the hypothesis that Carol murdered her stepmother. In the middle of it there's a close-up on Miss Quinton smoking a cigarette, but in the wide shot immediately following that, she isn't. (01:21:10)
Continuity mistake: When Nadine gets up from the chair to confront Poirot about implicating young Ginevra, she puts in a haste her shawl on the plate in front of her, but it's perfectly rolled in during the rest of the scene except another shot. (01:23:35)
Continuity mistake: When Lennox Boynton scoffs "What motive, for God's sake" at Poirot's accusations on his wife, the position of his right arm and the position of his hat under the sun have changed from the previous shot. (01:23:55)
Continuity mistake: When Lennox picks the wristwatch from his mother's lap showing the actual events, the natural light of the scene is entirely different between shots - the skirt is sunlit in close-up, in the shade in the other angle. (01:25:45)
Continuity mistake: When Carbury mentions Wallis Simpson to Lady Westholme, he's holding his baton alternating an overhand grip with an underhand one. (01:26:40)
Continuity mistake: During the coronation ball, Poirot explains that the murder must have not been intimate enough with the victim to tamper with the heart tonic. As he says that, his pince-nez are on his lap, but they are in his breast pocket a moment later, and it switches position again when it gets back to the same camera angle. (01:29:30)
Continuity mistake: When Jefferson Cope says "I admit" during dinner, the position of his hands changes in the mid-sentence cut. (01:29:50)
Continuity mistake: Just before Poirot moves to the other side of the dinner table after revealing lady Westholme's deception, Dr. King at first has both hands on the table, but in the next shot she is in a different position. Same for Jefferson Cope and his cigarette; he's smoking, then he is not. (01:33:55)
Continuity mistake: When Dr. King asks Poirot why would the culprit, of all people, kill Mrs. Boynton, Lennox next to her has her fingers crossed together, but in Poirot's reply he has the closed fist against the palm, and his wife's position is different as well. (01:35:05)
