Revealing mistake: When Freeth, Carter and Regan raid the flat, Freeth breaks the door down - the door starts to fall before Freeth hits it.
Revealing mistake: When Nathan and Audrey are sitting at the table in The Grey Gull, the extra in the background can be seen bringing a loaded fork inches short of his mouth then fake chewing. This happens a few times before cutting to the ending credits. (00:40:05 - 00:40:55)
The Million Dollar Bond Robbery - S3-E3
Revealing mistake: All the Liberty Bonds loaded in the bag of Mr. Ridgeway have the exact same serial number. (00:20:00)
Revealing mistake: On his way to be crowned, you can see the Pope's sneakers under his robe.
Revealing mistake: At the end when Laurel and Hardy are licking Columbo, a substance is caked on Columbo's neck, presumably the food they used to get the dogs to lick Peter Falk.
Revealing mistake: Halfway through the show, the officers get a flat. As Malloy is getting ready to jack up the car, Reed starts using the lug nut wrench to loosen up the nuts. He repeatedly turns the wrench clockwise, which would tighten the nuts.
Revealing mistake: "Who Killed the Rest?" The boat we see speeding toward shore explodes - but in the brief shot of it just before the detonation, the substitution of a model is apparent. The two vessels don't look anything alike. (00:02:00)
Revealing mistake: As Harm & Mac are returning to the US, we are told they are flying out of London Heathrow. But the stock footage of an airport used is actually London Gatwick, identified by its distinctive control tower, and not Heathrow.
Revealing mistake: The left pinball in the arcade (which later disappears) has the body of a "Star Trek TNG" machine - but the backglass is purely fictional. (00:17:45)
Revealing mistake: Paul Devildis calls the bank to discuss his restructuring plan. During the shots of the two bankers, on the desk is a notebook-sized, plain brown box. It is very distinctive as it is blank except for a single square white label on the front. Later in the episode Paul delivers his restructuring plan with the bomb inside to the bank. It is in this same box.
Revealing mistake: In the scene where Cooper takes the homeless man's photo on his iPhone, if you look to the bottom left of his iPhone's screen where it shows pictures that you have already taken, you can see that the homeless man's photo has already been taken, indicating that perhaps this scene was shot a few times, and the photos taken during those scenes were never deleted.
Revealing mistake: It's a valiant effort, but the scenes of Sherlock & Irene in a London street are shot in New York. Not only is the architecture wrong but you can see a U.S. pedestrian crossing signal over Irene's shoulder. (00:16:15)
Revealing mistake: Near the end of the episode, when Dr. Ogden and Murdoch look closely at Lukas' dead body (right before the candle scene), the "corpse" takes a deep breath.
Lead Horse Back to Stable - S1-E11
Revealing mistake: When Danny and Colleen are fighting in the rain at the end of the episode and Danny starts explaining how they should stop fighting, raindrops from the camera can be seen dripping from the top left of the screen.
Revealing mistake: Some of the punches don't land when Linc and C-Note are fighting the bad guys in the garage. This despite the sound indicating they are landing.
Revelations - S1-E10
Revealing mistake: When Kieran looks at his phone in the car, the image of Emma calling him is upside down. The image was added after the filming was done.
Revealing mistake: When Denise is showing Brad how to kiss, the first kiss is a typical "stage kiss" with their lips pretty clamped shut, but she then details what he's doing wrong with his tongue, which clearly wasn't at all involved with the sort of kiss they just shared.
Revealing mistake: When Lizzie awakens on the morning that Edith gets released, Edith doesn't respond and Lizzie goes to her bed to "mourn" the passing of her friend. Except that Edith is still breathing.
Revealing mistake: When the target's iPhone rings and Christopher Chance answers it, he swipes his finger across the bottom of the screen, which is the regular gesture to answer a call on the iPhone. Trouble is that we see the screen at the time, and it's not showing an incoming call, just some sort of list - he swipes his finger over nothing of any significance at all.
Revealing mistake: In the scene where the wife comes in to the morgue to view her dead husband, who she helped to euthanize, the dead man is breathing throughout the whole scene. You can see the sheet rising and falling at his stomach. (00:22:15 - 00:24:05)