Factual error: Poirot is visiting an art exhibition with the Countess, and expresses his admiration for a painting by Marc Chagall. Amazingly enough, that painting is "Les Plumes en Fleurs", something Chagall will create in 1943, years after the time when this pre-WW2 episode takes place. (00:24:50)
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 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 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)
Factual error: Hastings and Miss Lemon decide to investigate on their own. In the outside view of the first suspect they go question, a large contrail is visible on the left of his building (contrails were not a complete impossibility in the 30s, but it's rather odd to randomly see one in an establishing shot for this timeframe). (00:22:40)
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
Revealing mistake: In the reveal at the end of the episode we see a prolonged close-up of the newspaper "Nairobi Daily Press." Not only the fateful article linked to the murder is written in a font different and larger from the one used in the rest of the first page, but you can also see where the fake part abruptly ends, resuming mid-sentence the article of a real (or realistic) newspaper used as base for the prop, back to the right font and consistent style. (00:50:30)
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: 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: 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)
Character mistake: Hastings and Miss Lemon return to the apartment after their visit to the various suspects. Hastings though closes the door leaving the key in the hole, outside. (00:29:20)
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)
Wasps' Nest - S3-E5
Plot hole: There are some additions to the original short story in this dramatization, but they create a little problem since Hastings does not come with Poirot for the finale, and in fact is told to stay home in a rather demeaning way. Without Hastings, it's hard to imagine Poirot could break into Langdon's house, since Capaldi when is not playing creepy clown is a sculptor working at home; Poirot would need an accomplice to create a diversion. And, even sillier, Poirot tells Hastings to go buy him some washing soda, but he needs the soda to pull off the switch. Hastings should have joined him at least to give him the soda once Poirot has visited the doctor.
Wasps' Nest - S3-E5
Factual error: When we see the cover of Vogue magazine where Molly Deane appears, the recreation is not bad (the lettering used is not a classic Vogue one but something very similar was used for instance in August of the same year as portrayed), but the bar at the bottom gets the date wrong, putting it down as September 10th 1935, when Vogue always had 1st and 15th of the month as date of the release, no matter the day of the week. Also, it completely omits for instance the price. Would be a pretty difficult magazine to sell without that, real Vogue covers have that detail prominently displayed. (00:03:20)
Factual error: At the end of the episode, Hastings is reading a sports newspaper. The episode is set in 1935, and a weekend, but what he is reading there announces the jockey Billy Parvin substituting Fawcus riding Galdennis, and Golden Miller and the ticket for the sweeps, making the newspaper a March of 1933 one. (00:50:55)
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)
Factual error: Florence Carrington is killed on the train while she is leaving London for the weekend. When Poirot and Hastings examine the newspapers she could have been looking the day she was killed, the headline of "The evening news" in Poirot's hand announces the world record set by Malcolm Campbell at Bonneville Salt Flats in Utah, which happened on 3 September 1935, a Tuesday. (00:27:40)
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)
