Factual error: A scene in a photographic darkroom shows Michael Gambon developing a colour print in a dish under safe lights. Not possible. Colour printing must be carried out in pitch dark usually inside a light tight print processor, as colour photographic paper is sensitive to all wavelengths of visible light.
Revealing mistake: When the thief places The Blue Carbuncle in the goose's throat, it's obvious he actually doesn't put the gem in the bird's mouth. He pretends to, but then drops the gem into his other hand. This is all visible in the shot.
Factual error: Noticed this watching season 2, and I assume it was also the case in season 1. The entrance of the Miramar Playa has flags from various countries flying. One of them is the Canadian flag with the maple leaf. Wrong flag. In that period the Canadian flag was the "Red Ensign", or "Dominion Flag." The maple leaf flag wasn't introduced until 1965.
Episode #1.4 - S1-E4
Revealing mistake: The tabloid story with the plight of the Latimers just came out, and various characters are looking at it. In the bit when David Tennant tosses on the desk his copy of the Herald, the second paragraph of the second column goes "Sitting in the family home, surrounded by pictures and mementos of Danny" etc. It is the same text that was at the very beginning of the article when the store owner was looking at it. The newspaper is a prop with the same text in a loop. (00:35:00 - 00:36:30)
Episode #1.6 - S1-E6
Continuity mistake: Sami takes Maya directly from the location where Tommy Dark's body is found to his home, but Maya's outfit is completely different when they arrive.
Plot hole: When Nicky goes into prison in Mexico to give a criminal a shot of insulin, two errors are seen. 1) The needle and syringe are far too big for an insulin shot, which takes a one ml syringe and a small sub-cutaneous needle. 2) When we first see the syringe, there is a small amount of insulin in it, but it grows the more times we see it, until a large syringe is two-thirds full - insulin is enough in a one ml syringe.
The Secret Fate of All Life - S1-E5
Continuity mistake: The first time we see Detective Cohle being interviewed by the other two detectives, two of the beer cans on the table in front of him completely vanish between shots when he asks to see the rest of the discovery file.
Continuity mistake: When Buzz and Provenza race out of the squad room to follow Rusty in the frantic search for Stroh, Buzz is in shirt sleeves with no tie. However when they arrive at their destination Buzz is wearing a coat and tie.
Factual error: In the banner for the exibition in France at the start, the French isn't right. It says "Opéra nationale" and "La morte de Marie Antoinette Des objets fabriqués de le temps de Marie Antoinette". It should be "Opera national" and "La mort de Marie Antoinette Des objets fabriqués à l'époque de Marie Antoinette" or "des objets fabriqués du temps de Marie Antoinette".
Continuity mistake: Tony Sparkle is seen defacing a picture of Judy Talent. He starts writing something beginning with T. The action cuts away for a moment, and then back again. The words on the picture are "SAD OLD BAT". (00:07:05)
Continuity mistake: Jamie and Adam are shooting at Police badges to see which one would potentially stop a bullet. When they get to the third badge, it is held up to the camera. It says 'Jamie Hyneman' on the badge. The badge is then shot, and shown again to the camera. This time the engraved writing on the badge has changed to 'Adam Savage'.
Us vs. Them - S2-E2
Factual error: We see Liam's driver's license. It says he's from Rhode Island, but the license looks nothing like RI's. It's issued by the State Motor Vehicle Commission, but RI does not have an MVC (only New Jersey does). And the expiration date is always the same as the holder's birthday, but here we see it's 2 days after his birthday.
Backlash of the Hunter - S1-E1
Continuity mistake: Rockford's car has license plate number "835-OKG" at the front of his car, but license plate number "853-OKG" at the back of his car, a few times during the episode. (00:35:40 - 00:37:50)
Visible crew/equipment: As Joe approaches the third car with the bad guy in it, there is an unknown man, possibly a crew member, reflected in the back window where there wasn't a man before.
Continuity mistake: Kurt is still recovering from the beating he took in the previous episode with bad cuts on his forehead, checks and temple area. They are red and impossible to miss while he is in the police station. The cuts have miraculously disappeared in the next scene when he goes to visit Mona.
Here There Be Dragons - S2-E11
Visible crew/equipment: When Prax leads the group to where Dr. Strickland took Mei, just as they reach the door the two green and yellow T-marks are visible on the floor. (00:02:30)
Character mistake: A shot shows Djimon Hounsou completing his year entry on a large chalk board. The entries are 20 years apart. The third entry on the second line is 2274, the next should be 2294, but instead it records 2394. The one after corrects the sequence with 2314. Considering there is an entry only every twenty years, you would think he'd be more careful. (00:20:15)
Factual error: About 45 minutes into the episode, the girls' car stalls because the alternator's wire has been removed to cause this. For a car to stall like this, the battery has to be heavily drained which it would wind up being. When the killer comes up to the car, he tells her to try and start the car. She does and it turns over but doesn't start. The battery would never have enough amperage to turn over the car if it didn't have enough to keep the motor running.
Factual error: There is no way cops would just walk up and open fire on a suspect unannounced, not knowing if he is armed or not, and with an innocent bystander so close.