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?
The Bye-Bye Sky High I.Q. Murder Case - S6-E3
Factual error: A "silencer" (properly called a "suppressor") does not muffle a gunshot to a whisper. An unsuppressed gunshot is about 160 dB, equivalent to a jet airliner taking off, but a suppressed gunshot still registers about 100 dB, equivalent to a power lawn mower. Also, a suppressor on a revolver is totally useless, because most of the noise comes from the gap between the front of the cylinder and the rear of the barrel.
The Most Dangerous Match - S2-E7
Factual error: Clayton tells Columbo that he had purchased a new transistor for his hearing aid. Hearing aids - even the old types in use in the 1970's - do not have any user-replaceable parts. The only thing that can be replaced is the battery.
Other mistake: Several of the English characters change back and forth between calling Columbo "leftenant" and "lootenant."
Other mistake: When Benedict puts his briefcase in the back of the Jaguar, the hatch does not close properly. It is still not closed properly when he picks up the car from the repair shop.
Factual error: Columbo asks for a red wine. His host orders a Beaujolais but the butler brings a Bordeaux. Beaujolais is from Burgundy, not Bordeaux. (01:18:40)
Dead Weight - S1-E4
Other mistake: Columbia calls Helen Stewart from a pay phone. He dials only six numbers, not seven.
A Bird in the Hand... - S11-E3
Continuity mistake: At 8:15 AM, Harold McCain telephones his Aunt Dolores but when she answers the call, the clock on her mantel shows the time as 10:20.
Short Fuse - S1-E7
Continuity mistake: A chauffeur is driving Mr. Buckner to a mountain cabin. It is 7:30 pm and a very heavy rain is falling. The car explodes, killing both men. When their bodies are located the following morning, the road and the surrounding hills are completely dry. There are not even any puddles.
Continuity mistake: During his lunch with Brimmer, Columbo's wine and water glasses switch places several times. (00:00:50)
Plot hole: When Columbo presents the flipped photograph to Dick Van Dyke in the final scene, Columbo insists it is correct and proves DVD guilty. But Columbo already showed him the rejected fireplace photo, which shows the room arranged correctly. It also shows the victim's wedding ring, which would be on the wrong hand according to Columbo.
Suggested correction: It's all part of Columbo's bluff: Galesko wants to get rid of Columbo as fast as possible and believes himself to be too smart, thus falls for it. Galesko might have forgotten about the fireplace photo or underestimated its importance. Even if Galesko points out the rejected photo: Columbo is already bluffing about the first photo, he can very well just claim the second photo never existed or is destroyed too, leaving Galesko in the same position as he is before he incriminates himself.
The Most Dangerous Match - S2-E7
Other mistake: The police photographer takes a picture of the garbage grinder. His camera has a flash, and the photo is indoors, but the flash does not fire.
