Deliberate mistake: Richie was an infant in season one, and beginning with this season, he has been aged up to at least 3 years old while none of the other characters have aged up.
Deliberate mistake: In the scenes that take place in Kentucky, none of the characters speak with a Kentucky dialect.
Deliberate mistake: Elliot threatens Olivia about her testing positive for Oxycontin because she drank a peppermint mocha he brought her. If she tests positive she loses custody of her child. The thing with Oxy is that it's in one's system for a maximum of 4 days. Could be even less if only a small amount was taken and somebody exercises and drinks lots of water. Somebody could also eat poppyseeds and that would give a false positive. She could say she ate a poppyseed bagel. (00:14:00 - 00:16:00)
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: *SPOILER ALERT* Behind T-Bag is the actor who plays Lechero, and Lechero had just died in the episode. The person was not Lechero, but maybe they didn't have another extra at hand to replace him. 'Time 1' and 'Time 2' are taken from Netflix at the time this was posted. (00:29:46 - 00:30:25)
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)
Log 1: The Impossible Mission - S1-E1
Deliberate mistake: Halfway through the episode, they are chasing car thieves in a drainage channel. The thief's car comes to the end of the road and crashes into a deeper gully. You can see that the windshield has been taken out of the car, although it was previously there. They cut away and when they come back, parts of the windshield are back in the car, but the whole center is missing.
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)
Crucifixed - S5-E10
Deliberate mistake: When Tara is talking to Gemma in the parking lot of Stockton Prison, the chrome bumper of Tara's SUV is blurred out, probably to cover up visible crew and equipment. It looks unnatural, since the image is sharp enough that you can see the radiator itself behind the grille, and the numberplate is perfectly sharp.
Deliberate mistake: Around the 26 minute mark, when Charles Brandon joins Margaret for a game of cards during their voyage to Portugal, Margaret has a glass of wine (and later Brandon) in which the liquid is not sloshing around As It Should Be on a ship that is rocking and swaying the way it should. (00:26:10)
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: Unavoidable, but still noteworthy: At the beginning of season 2, all the story lines pick up where they left of from at the end of season one; indicating that not much time has elapsed. In spite of this, most of the cast have different haircuts, Dana has grown out her fringe, and Tina suddenly has a baby bump.
Deliberate mistake: In the episode January 2011 where Stephanie puts a slide in the living room, when Stephanie goes down it, you can see she is using a stunt double because her hair is thicker and they cover her face with her arm.
Deliberate mistake: Shawn fishes Mr. Feeny's watch from the septic tank and mentions the septic tank is deeper than it looked. Given this, he should be covered in human waste, instead of just looking a little dirty.
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.
Deliberate mistake: Identical twins Beverly and Elliot have the exact same beauty mark on their faces, roughly on the smile line directly across from the right nostril. Identical twins don't share features like that.
Deliberate mistake: After Taylor leaves Amanda's hospital room in a fury, she goes to a pay phone in the hallway and dials Nick's number without inserting any coins.
Containment - S1-E11
Deliberate mistake: Sunny is the teams SAW (squad automatic weapon) gunner. He carries an FN MK46 which is a special operations version of the M249 SAW. The MK46 unlike the M249 only takes belt-fed ammunition from 100 or 200 round "nutsacks." On this mission Sunny is wearing a chest rig with STANAG mags and no nutsacks. He has no backpack for extra ammo either. He hands off his MK46 to the Jason whose staying behind and no nutsacks. Plus he doesn't take Jay's HK416 rifle in the swap. Usually people swap one for one. (00:31:15 - 00:32:00)
Deliberate mistake: We see the Air Force plane's bomb bay doors come open. But in the next shot of the plane banking, the doors are instantly closed again. (00:45:20)