Plot hole: When Columbo tries to explain the position of the cars and the angle of the shot, he gets to the version when they come to the conclusion that if the car behind the other car park one way than the first car wouldn't block the light, so the shooter could see the victim. Colombo says it is possible, but in that case it wouldn't explain the angle of the shot. However there could have been 2 shooters which would instantly answers the question, and Columbo wouldn't come to the conclusion that it was a mistaken identity case. (00:43:00)
Deliberate mistake: Beth shoots Bryce three times in the chest, and he falls face down on the floor. She then drags his body across the floor, also face down, to in front of the sliding door, but there is no sign of blood anywhere.
Suggested correction: In the early Seventies, no television show used blood effects. They were too expensive and would severely restrict potential audiences as television channels were notoriously conservative in those days. This is a creative and technical decision, not a mistake.
Dead Weight - S1-E4
Plot hole: How did the revolver get into the museum after the murder? Falk said he did not see it in the packing crate.
Factual error: Near the end of the episode, Jackie Cooper fires a bullet into his hotel room from the balcony using a revolver fitted with a silencer. Hayward also uses a revolver with a silencer to kill Stone. This is a classic Hollywood error, as silencers do not work on revolvers (unless noticeably modified), due to the gap between the barrel and the cylinder. They also don't make gunshots nearly as quiet as shown.
Continuity mistake: The insurance agent has a complete hot dog in his hand while Columbo talks. When we cut to a view over his shoulder, Columbo's sentence continues but the agent is suddenly chewing. When did he take that bite? (00:36:20)
Character mistake: In the performances, Benedict is not conducting; he is waving his arms around.
Factual error: When Mrs. Williams takes Columbo flying, she does some aerobatics. Neither of them is wearing a seatbelt. No pilot would do that.
Character mistake: A valet tells Columbo that automobiles belonging to Sauri embassy personnel are repaired at a service station two blocks away. Later, when Columbo is speaking with Hassan Salah, he says, "I know your cars are taken to a service station three blocks away."
Character mistake: During a rehearsal, conductor Alex Benedict instructs the orchestra to play "quasi un fantasia." Columbo asks Benedict's wife Janice what those words mean. She tells him, "It's Latin for 'like a fantasy." The words are Italian, not Latin.
Death Hits the Jackpot - S11-E1
Continuity mistake: After Lamarr takes off Freddy's undershirt we see the level of the water in the bathtub. Then he drags Freddy over to the tub and breaks his watch. At that time the water level is lower than it was before, even though the water was still running.
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.
Any Old Port in a Storm - S3-E2
Plot hole: Carsini has a wine vault (with very expensive wine in it) with an integrated air conditioner. There are indeed wine vaults like that. But mostly active cooling wine vault are used by "amateur" wine lovers (who can't afford an underground cellar) but not by wine connoisseurs like Carsini. Active coolings are not very reliable. A power failure or a simple malfunction and Carsini would lose all of his expansive wines he collected for many years (like we saw in the episode). So why shouldn't a huge wine connoisseur build a cellar, surrounded by cooling soil where temperatures never rise that high? He is rich, he as a big estate, a villa, and he knows better to store the jewels of his passion adequately. Why store wines in a potential oven where high temperatures (without air conditioning) can even kill a man (his brother) in the first place? It is a far fetched and an unnecessary gambling just to have a murder-plot.
Continuity mistake: When Columbo takes the whiskey decanter out of the murdered man's liquor cabinet, he puts his cigar in his mouth with his right hand and opens the bottle with the same hand. A second later, the shot changes to a closeup of him sniffing the contents and the cigar is back in his hand. (00:28:55)
Short Fuse - S1-E7
Continuity mistake: As Roger helps Columbo remove the pink Silly-String from his hair, the amount and configuration of the string differs radically with each change of camera angle. (00:37:30)
Other mistake: Kingsley doesn't know if his victim is married or unmarried, whether or not he has children, if he has a maid, but he brings a hand vacuum and empty vial to the murder to collect cat hair from the victim's cat to plant on Clifford's jacket.
Continuity mistake: In the living room of their home, Lesley Williams shoots her husband in the chest. As he falls, he knocks a lamp off a small table. Lesley puts the lamp back on the table, but in all the following scenes in the living room the lamp is gone. (01:00:00)
Undercover - S12-E3
Continuity mistake: Columbo ushers Krutch and Susan into an office for questioning. When he closes the door, the venetian blinds on it change from straight to misaligned and back again between shots.
Continuity mistake: When Columbo questions her about the carnations, Janice Benedict's sweater is either off her shoulders or covering them completely, depending on the shot. (01:11:00)
A Deadly State of Mind - S4-E6
Plot hole: (Spoiler) Mrs. Donner screams in fright just as she jumps to her death from her balcony. This seems unreasonable since she believes herself to be going for a swim (under post-hypnotic suggestion) The scream is heard by a later witness to help establish time of death. If she suddenly realized the deadliness of her act, why would she continue with it?
