Continuity mistake: When Gertie and Joey make their escape running down the stairs of the hall, they pass by a couple (she has a white hat and a blue dress). When Poirot and Japp run after them, the same couple has jumped back several meters. (00:43:00)
The Disappearance of Mr. Davenheim - S2-E5
Continuity mistake: When Poirot at dinner asks the first question (the bathroom one), he does not have his large napkin in his vest. When he asks the second one (the bedroom one), the napkin he had for all the rest of the scene is back. (00:40:15)
The Disappearance of Mr. Davenheim - S2-E5
Continuity mistake: When Poirot does the newspaper trick for Miss Lemon, the final reveal has him present the newspaper holding it between index and thumb in the front view, index and middle with the thumb sticking out in the back view. (00:42:10)
The Disappearance of Mr. Davenheim - S2-E5
Character mistake: The magician's assistant wears a costume that leaves her legs exposed, and the costume itself vanishes. The trick can't go as Poirot describes to Hastings and Japp (and it is made with a TV editing trick). (00:07:05)
Continuity mistake: Hastings sits down when Japp is having his meal at the inn, and eats one of Japp's sandwiches. In the rest of the scene, the sandwiches on the plate change position and Japp's beer has been replenished a bit. (00:35:00)
Continuity mistake: When not-so-Lavington is spying Japp and Mad Dog Poirot outside of the station, he is holding the wheel with his right hand at the top, but a moment after he's using that hand to smoke instead. (00:34:35)
Continuity mistake: Poirot opens the "intolerable" letter Miss Lemon hands him; camera in the door and he has his finger between envelope and letter, reverse shot and he is holding them parallel together. (00:33:45)
Revealing mistake: The phone book has a LMS logo on the page edges in the close-up where we see Poirot actually flip through - the logo disappears when he is moving the book in the rest of the scene. (00:16:10)
Continuity mistake: When the box opens revealing the jewelry, the jewelry is scattered differently each time it is seen. The box itself gets closer to the table's edge when the lady nabs the jewelry. (00:40:40 - 00:42:40)
Continuity mistake: Poirot and Hastings are talking with Freddie, by her invitation. She says "You'll be giving me a diploma next" and three extras walk by her chair. In the following shot she completes the action of standing up, but the extras are still there, behind their original positions. (00:44:15)
The Disappearance of Mr. Davenheim - S2-E5
Continuity mistake: Carving the distant relative of his parrot for dinner, Poirot slices one side in the close-up, which turns out to be the exact opposite side in the wider shot. (00:38:35)
Continuity mistake: Lavington puts his hat on the couch before talking to Poirot. The hat shifts closer to Hastings and then back closer to the armrest during the scene. (00:12:45 - 00:14:30)
Continuity mistake: Lavington arrogantly sits in Poirot's study and opens his cigarette case, closing it after. In the following close-up, the case is open again. (00:13:15)
Continuity mistake: Poirot reads the telegram after the opium den raid. The letter is in his left hand, but moves between shots to the right hand. (00:40:40)
The Disappearance of Mr. Davenheim - S2-E5
Continuity mistake: When Poirot's castle collapses, the cards are all in perfect order, but become scattered after the cut to Japp. (00:35:40)
Continuity mistake: The level of sherry in Radnor's glass changes after Hastings smiles at him when Poirot is laying the trap. (00:38:40)
Continuity mistake: After reading the will of the deceased, the lawyer folds back the first page twice in two different shots. (00:26:05)
Revealing mistake: As he scolds Hastings for his pancreatic hullabaloo, Poirot drinks his tisane from an empty cup. (00:02:55)
Revealing mistake: The stuntman smashing through the window is quite obvious - he does not even have the hair styled like Hastings'. (00:31:30)
Factual error: Japp in this episode uses a Humber Snipe, a 1937 model. The story is set in 1935.