Factual error: Possibly a mistake from the novel on which the series is based, but although he later became Bishop of Hereford, St Thomas Cantilupe wasn't baptised in Herefordshire. He came from Buckinghamshire.
Continuity mistake: When Mary talks to Bobby D at the crime scene, her hair moves back and forth over her left shoulder between shots throughout their conversation.
Other mistake: Agent Maddy is approaching the scene of a downtown explosion and fire. She has her FBI badge showing on her belt. As she approaches the police line she rummages in her jacket and looks down at where the badge is, but reaches into the adjacent pocket to pull out another badge in a wallet. Why not identify herself with the badge on her belt?
Plot hole: After Jack's wife disappears for a couple of days, he receives a call from her cell phone from the cab driver who found it. Jack arranges to pick it up from a hotel. After he picks up the phone, its battery dies as he checks it, at 12:13pm. In the next scene with Jack, he's in a bar with the phone plugged into a charger; when it comes on, he checks it - the battery shows 3%, but the time is 9:13pm. He apparently wasted 9 hours when he's in pursuit of his wife's mysterious disappearance before plugging in the phone. A scene later, the time is now just a minute later at 9:14pm but the battery is now charged to 79%. (00:37:25 - 00:40:45)
Continuity mistake: When Nick's mom tells him to show Gypsy around she takes the cigarette away from her lips. A shot later it's back in.
Continuity mistake: When Irina meets XIII on the river dock, she leaves her car, closes the driver side door and walks to XIII. Moments later, when XIII is shot, she runs back to her car, where the door is wide open.
Angel of Mercy: Part Two - S1-E4
Character mistake: When Lenore Osgood is speaking on the phone with Charles Wainwright about killing Dr. Hanover, she mispronounces "Larynx" as "Lar-nix."
Factual error: A British soldier in 1940 says he was educated at the University of Warwick. The university wasn't founded until 1965.
Continuity mistake: When Dr. Zaius and the gorilla soldiers ride up to the crashed spaceship, his hair is mussed in the long shots and properly groomed and neat in the close ups.
Factual error: When Detective Inspector Sara Lunt's photograph in uniform is shown on the TV news she is wearing a double row of silver lace below her hat badge. Only chief constables wear this insignia, well above the rank of inspector.
Factual error: Constantine's driving licence is shown - it's a UK licence, but no. 7 where his signature should be is blank, and no. 8 where his full address should be simply says "England, United Kingdom." Both are printed onto the licence when it's issued - without that info it would never be issued in the first place. And it's not a fake, because why would he have a fake licence with his real information on it? It's just an incomplete prop.
Royal Jelly - S2-E1
Plot hole: It's all very well for Albert to humm "bzz-bzz" to indicate that he has been eating too much Royal Jelly and is no longer entirely human. But "bzz" is just the noise of bees flying, it's not a sound that they deliberately produce. It makes no sense to SAY "bzz." Suppose he was turning into a horse instead, then he might say "Whinny!", but he wouldn't say "Clip clop clip clop."
Revealing mistake: There are bullets placed on the counter, the one casing has a hole in it from being drilled to show it's a dummy round and there's no gunpowder in it. (00:14:45 - 00:15:20)
Factual error: DI Renton is a Metropolitan Police officer 'parachuted' into Kent to solve a big case. This hasn't happened for many decades. Local police forces investigate their own crimes without help from the Met.
Factual error: The DI refers to the local policeman as "Officer" Fuller. No British police officer would use this term to refer to another British police officer. She'd have said Constable Fuller or PC Fuller.
Visible crew/equipment: When Rebecca Madsen jumps in her car to pursue the armored truck, as she does a U-turn and takes off at high speed, you can see all the people standing on the side watching the filming. Some even have their phone cameras out videoing it. (00:29:30)
Protect Her - S1-E1
Factual error: When Jules and Hannah are talking about the financial shenanigans at Owen's firm, Jules says that the owner of Owen's company had fraudulently driven up the price of the stock before the IPO. This is impossible. The IPO is the first time the shares become tradeable.
Continuity mistake: Toward the end of the episode, our intrepid heroes stash their large black bags as they run through the market. They run through the market for the next several minutes with only their machine guns. They later board the waiting speedboat but when they disembark, they have their bags.
Deliberate mistake: Per his own memoir, Gary Noesner was vacationing in Bermuda, celebrating his wedding anniversary, during the siege at Ruby Ridge. As one of the show's main characters, his insertion there was likely to keep him involved in the story.
Continuity mistake: When Marshall first finds Trip's letter, he holds it from the left side. In the close-up, he's holding it from the right side. (00:02:10)