Deliberate mistake: When Ryan and Esposito give Beckett the surveillance tape of Sophie and Uncle Teddy, Beckett's computer reads the disc and plays the tape incredibly fast. Faster than any desktop PC I've ever seen.
In Which We Meet Mr. Jones - S1-E7
Deliberate mistake: Dunham comments that she works for Homeland Security. While the FBI is under the jurisdiction of the Justice Department, she works as part of a special Homeland Security task force; so saying she works for DHS is an accurate statement.
Deliberate mistake: In the episode "Bunk," a man goes in the house looking for his cat. When the cat releases the fumes, it jumps down, but when the man dies, the cat is nowhere to be found. The cat is not mentioned ever again in the episode either.
Deliberate mistake: Because the series changed networks after the end of season one, this episode completely ignores that season's cliffhanger about Harm being arrested as a suspect in the murder of Lt. Schonke.
Deliberate mistake: At the end, a line apparently cut earlier creates slight confusion. Nick says to Nat, "When LaCroix asked you why?" (why save vampires). In the earlier scene as shown, the elusive LaCroix spoke only briefly to Nat in the lab, and never asked her that question. (00:42:20)
Deliberate mistake: The day of his scheduled departure, Poirot overhears conversations (mainly the one from the window of his room) he couldn't possibly be hearing given the long distance outdoors and the tone of voice. His reactions are shown as if he could hear and not simply see and infer the meaning. (00:23:00)
Deliberate mistake: Because the opening narration was adapted from the original American series, the phrase describing the role of the Crown Prosecutors (e.g. "prosecutors who prosecute") is redundant.
Deliberate mistake: Florence and Humphrey set up the scene using a printer that is nothing short of magical; the photos, in color, come out from the machine the instant that Florence displays the profile on screen. It is obviously done to speed up the scene - however, Florence could have printed the pictures beforehand and hand them to Humphrey one by one as she reviews on screen the profiles, there was no need to have them come out fresh from the printer with that kind of impossibly fast timing. (00:15:00)
Deliberate mistake: When Sam first meets Mickey (who is posing as a bank robber), Mickey says he needs Sam to state that he needs Mickey's help in robbing a bank, so if Sam turns out to be an undercover cop, Mickey can plead entrapment. This is a classic error. Entrapment only exists where a cop actively persuades a criminal to do something he otherwise wouldn't have done - which is not the case here. If Mickey as a con artist knows this (which is likely), it's a deliberate mistake, otherwise it's a factual error. (00:30:09)
The Secret of the Unicorn: Part 1 - S1-E3
Deliberate mistake: After Francis Haddock kills Red Rackham, he lights a fuse to the explosives. The fuse that was lit is only a foot long, yet he is somehow able to climb out the ship without anyone noticing, get into a boat and swim all the way to land before it explodes. At a foot long it would have exploded in 10 - 15 seconds, all of that would taken at least 10 minutes. (00:18:45)
Deliberate mistake: Probably best for filming the scene, but Jennifer Hart pulls up and parks her car on the street on a red curb in front of an ambulance and walks away. (00:10:12)
Deliberate mistake: After it is revealed Won-hyung has taken over Yeom's body, he is shown walking alone on the street and says aloud "She's not afraid of going to Hell? I can't make it so easy for her. Will she be able to leave behind the person she's been pining for so easily? I can't wait to watch the heart-rending sight." There is no reason for him to say this out loud. He is alone and not talking to anyone. The only reason he is saying this is so that the audience knows his plan. (00:33:23)
Deliberate mistake: Rick is talking to Joe in a maximum security facility through glass without a phone. It is impossible to hear through such glass. One would literally have to scream and still it would be difficult to hear. They should be on a two-way phone and those conversations are at times recorded, especially with high profile prisoners like murderers, mafiosi, terrorists. There's no way they would get away about discussing murder and revenge without an intercept. (00:14:00 - 00:15:00)
Deliberate mistake: When filming the fake movie with Sophie playing the nun, many holes are made in the door, but when she slowly kneels to the ground, there isn't a hole behind her, so it seems like she's been miraculously saved. But as the scene continues, the nun starts to bleed and dies. Technically, they couldn't safely put a squib that close to her. (00:21:15)
Deliberate mistake: As Chief Vickery, in present time, patrols Wind Gap in his car he passes by the barbershop. From his POV, through the car window, we see four men sitting outside. The same men were also seen in Episode 01, but from young Camille's POV as she and her sister pass by the barbershop in 1992. The show hid a load of easter eggs and signs throughout all episodes. They would hardly make such a mistake. More likely, the repeat was to underline Vickery's backward, stepfordian attitude.
Just Let Go - S1-E4
Deliberate mistake: When Devon does an internet search for Chucky, pictures of Tiffany and Nica pop up. But they're still-shots from "Bride of Chucky" and "Cult of Chucky." It makes no sense that they'd be in an internet search - nobody could have taken those photos.
Deliberate mistake: During the episode, whenever daily newspapers are shown, they lack any indication of the date.
The Campground 'Bizarre' Case - S1-E17
Deliberate mistake: The evidence that proves Kindaichi's alibi is the store receipt detailing the time of his purchase. Notice that the year is recorded too, but it reads "20XY." (00:12:40)
Deliberate mistake: Though the series title is technically inaccurate, since in New York CSIs are called CSUs (crime scene units), it's called "CSI: NY" to tie it in as existing in the same universe as its sister series "CSI: Crime Scene Investigation" and "CSI: Miami."
Deliberate mistake: Though by 1964 it was already suspected (and later confirmed by Mariner IV) that Mars has an atmosphere humans can't breathe and temperatures too low for humans to tolerate, Merritt and his crew are here exploring the planet sans spacesuits. This was "fudged" because space helmets A)are expensive, B)reflect cameras, and most importantly, C)obscure the actors' faces. (00:24:00)