The Mystery of the Spanish Chest - S3-E8
Continuity mistake: When Poirot pulls out of the drill hidden in the handle, he holds it triumphantly in his right hand. In the next shot he mounts it on the handle starting the motion with the drill already in the left hand and the rest of the gimlet in the right. (00:40:00)
Continuity mistake: The Countess arrives at the hotel at the beginning of the episode. In the overhead shot she reaches the top of the stairs with nobody close to her, just the porters behind her, but in the next shot there are other people in the lobby, who at the next cut are even closer to her to fit in frame. (00:02:10)
Continuity mistake: At the end of the 'lovely day' with the Countess, Poirot stops a cab and opens the door for her. Just before the cut, notice a woman with a white dress and a brown hat crossing the street in front of the taxi. The extra crosses the street again in the same direction when he says "Oui" in the following shot. (00:28:50)
Continuity mistake: During the exhibition of the much acclaimed contralto, at one point it is shown that Lady Runcorn is going upstairs and is looking at the smoking person. Back to the host who is on his own at his table. At the first cut, suddenly there are more people standing in attendance in the background (pretty much everyone was seated earlier) and his glass has also refilled. (00:10:15)
The Mystery of the Spanish Chest - S3-E8
Continuity mistake: During the party, the colonel expresses to Poirot his disappointment for the jazz record being played, music "from the inferior races." He puts a tart in his mouth, closing his lips past the piece of fruit. Cut to the wider shot, and he is still holding a tart that sports the strawberry he just chewed on. (00:19:00)
The Mystery of the Spanish Chest - S3-E8
Continuity mistake: Poirot enters Japp's office when the inspector is dealing with the tribulations of modern machinery. As Poirot sits down, you can notice the crumpled paper by the phone being different in the reverse shot, when you can also see Japp's hand being at the corner of the typewriter. But he brings it up from his lap in the next shot. (00:38:15)
The Mystery of the Spanish Chest - S3-E8
Continuity mistake: In the flashback during Poirot's narration, the scene with Colonel Curtisstalking to the victim at the military club happens differently from the first time around, with Clayton switching hand position after a different line of dialogue, starting off in discontinuity with the previous shot (originally the continuity was flawless). (00:44:40)
The Tragedy at Marsdon Manor - S3-E6
Continuity mistake: Poirot and Hastings are in front of the corpse at Marsdon Manor. When Miss Rawlinson makes her comment about him taking advice, she is almost with her back against Hastings and in a dramatic light totally different from what shown in establishing shot. (00:17:45)
The Tragedy at Marsdon Manor - S3-E6
Continuity mistake: The morning after his arrival at the village, Poirot sits with Hastings for breakfast (prime minister Baldwin is mentioned on the radio). Hastings is holding the newspaper with his left hand and the right is on his knee. New shot and both hands are on the table. It keeps happening during the scene. (00:14:25)
The Tragedy at Marsdon Manor - S3-E6
Continuity mistake: Poirot holds the widow's painting for Hasting and asks "You do not see?" In the reverse angle with Hastings (obviously) not seeing a thing, Poirot's hand in frame is holding the painting differently. (00:39:15)
The Tragedy at Marsdon Manor - S3-E6
Continuity mistake: The car with Poirot and Hastings enters the village. Right as the camera begins to pan to the left, notice a woman with a maroon tailleur and a powder blue hat. She walks in the same direction of the car but turns around a moment later. Several seconds after, when we see the two protagonists in the car, the same woman can be seen amongst the passersby through the back window. (00:04:15)
The Tragedy at Marsdon Manor - S3-E6
Continuity mistake: When Mr. "Clarrisa" Naughton produces the manuscript to the unsuspecting Poirot, the open side of the folder is to his own right, but it ends up on the concierge desk turned the opposite way. (00:05:15)
The Tragedy at Marsdon Manor - S3-E6
Continuity mistake: Poirot slams the newspaper on the breakfast table when Naughton asks him if the accomodation "was all right." But it is turned in opposite directions at every cut. (00:14:55)
The Mystery of the Spanish Chest - S3-E8
Continuity mistake: When Major Rich is interrupted playing billiards, the shadows on the playing table have inconsistent angles between shots. (00:11:30)
The Mystery of the Spanish Chest - S3-E8
Continuity mistake: Japp hands Poirot the phone in his office holding it with the left hand, which turns into the right hand at the cut. (00:40:10)
Continuity mistake: Hastings buys a large scotch for Rupert Carrington. You can see in the wide shot Hugh Fraser with his right hand raised to give the coins to the bartender. But in the next shot, Hastings' hand is not in frame yet, and he even ends up paying with the left hand instead. (00:30:00)
Continuity mistake: At the hotel, the Count is checking in. Behind him by the revolving doors you can see three people having a conversation, with one being a woman wearing a distinct floral dress and brown stole. He steps away from the concierge and the same woman is having a chat in a different part of the hotel, right part of the frame. (00:03:30)
How Does Your Garden Grow? - S3-E2
Continuity mistake: Poirot asks Dr. Sims "So the Delafontaines, they were dependant" etc., the doctor's right hand changes position between shots, and the hand positions keep alternating between the two versions depending on the camera angle (an item suddenly appears in his hand when Miss Lemon mentions the living relatives, too). (00:26:30)
The Mysterious Affair at Styles - S3-E1
Continuity mistake: Poirot is concentrating in London, making a house of cards. When he says "I steady my nerves, that is all", the 6 of hearts can be seen in his right hand, and he sets it as the diagonal piece. Cut to Hastings, and then Poirot supposedly still has the same house in front of him...but it is not. Where the 6 of hearts was, there is now a 6 of spades, and the whole castle is different, with the cards pulled tighter together. Later he rebuilds the house, and he sets horizontally in the close-up a 5 of spades, which turns into the 2 of spades immediately after. (01:19:40)
The Mysterious Affair at Styles - S3-E1
Continuity mistake: The guests of Styles Court manage to get inside the room of Mrs. Inglethorp and talk to her before the second fatal crisis happens. In the first wide shot you can see Hastings peek at Lawrence and then look towards the fireplace, which is an action he'll do in the close-up that follows - Lawrence does not seem to look in the direction Hastings is checking out, at all, but that is actually a nice touch considering the resolution. Moreover, in the second close-up of Hastings looking at him (the one that follows the view of the fireplace), Mary is directly in front of Hastings, you can see her insignia and arm. But instantly she is shown at the cut, creeping along the wall behind Lawrence. (00:29:00)