Revealing mistake: When the plane approaches the aircraft carrier, they have to dump fuel, and the fuel comes out through the back. However it should be coming out on the wing tips. So they had a tank of water or something similar that they sprayed out through the back. (Confirmed by a Staff Seargent with the USMC who flew 8 years on a C130.)
End Game (1) - S8-E7
Revealing mistake: Boyd has a video-conversation with Linda on the phone she sent him. On top of the screen you can see how long the video will last (1 minute and 3 seconds), showing it's a pre-recorded video, not an actual live conversation.
Revealing mistake: When we first see the army of Starks outside Global Dynamics, it's quite obvious that only one of them is actually the actor that plays Stark; the others are merely people who look similar.
Revealing mistake: Episode 15, "Faceoff": When the agent fires the hook to get to the roof of the church, it does not reach the balcony. However in a following shot you can see the agent climbing there. (00:10:05)
Revealing mistake: When Briscoe and Green investigate the auto yard with the stolen, blue SUV, Briscoe handcuffs the owner. When he cuffs him, he turns him, showing his back and his hands behind his back. You can see the actor isn't cuffed, just holding the handcuffs as he walks. (00:06:35)
Near Death Experience - S12-E1
Revealing mistake: At the end Jack wrestles the knife out of the attacker's hand and in doing so cuts his own hand. However in the extreme close up you can see the rubber knife is bending when Jack wrestles it away. (01:30:30)
Revealing mistake: When Major Popov aims the rocket launcher at the Venus probe, there is no rocket in the launcher- it is just an empty tube.
The Tale of the Dream Girl - S3-E10
Revealing mistake: A kid running through the bowling alley moves aside to let Johnny, who is a ghost only his sister can see, pass by.
With This Ring, I Thee Kill! - S1-E7
Revealing mistake: In the hospital, a male nurse stands by as Rhodes talks to the patient, keeping an eye on all the beeping vital-signs monitors. But there's nothing attached to the man in the bed - no wires, no leads, not even an IV.
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.
The Blue Lotus: Part 2 - S1-E9
Revealing mistake: There's a shot where there's tons of people walking beside the train. The people that walk by repeat as the same people 2 times. (00:29:00)
Revealing mistake: When the band in the nightclub performs the made up song "Mr. Music Man", the suave Mr. Stone, the musician Miss Fisher ends up dancing with, is doing one heck of an hilariously incompetent job at faking to play an instrument, basically playing air-banjo strumming about 3 inches above where the chords are, and wildly off tempo. In the closing bit of the song (as the singer sings "To sin") he even moves his hand at the side of the strings and not above them. (00:03:30)
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)
Revealing mistake: When Chloe and Jack are in the car she is looking at the computer on her lap. The gear shift in the car is a automatic and it shows it being in park as they are driving. (01:20:10 - 01:20:55)
Revealing mistake: When Bob and Joyce have lunch, Bob pops open a can of soda (which is period appropriate). The scene cuts to Joyce, then back to Bob. It is clear from how he is holding the can, and how he pretends to drink from it, that his newly opened soda is actually empty.
Episode #1.7 - S1-E7
Revealing mistake: When the guitarist punches the bass player in the face you can see him miss. (00:50:02)
Revealing mistake: Mr Knight shoots Suzie Boreton - after the muzzle flashes and sounds stop the bolt of his MK14 EBR continues to move back and forth as if it's still firing. (00:30:30)
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.
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)
Revealing mistake: Hannah sits in a conference room and pulls a landline phone towards her to dial her friend, asking about the will Owen left. The phone however isn't in any way connected, hence no call could have taken place.