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.
Murder with Too Many Notes - S13-E4
Other mistake: In the movie within the story the murderer repeatedly stabs the victim and pulls back the knife. Even after several stabs there is no blood on the knife. (00:02:25 - 00:05:45)
Character mistake: In the grocery store scene Robert Culp sits on a display of pumpkins but there are 2 signs that say watermelons.
Suggested correction: As a retail worker of 18 years, I know that POS (signage) mistakes happen in supermarkets, for example a product is moved and the correct POS is not replaced. This scene seems to be filmed in a real supermarket meaning this is not a mistake made by the show's producers, however if this was filmed in a studio, "Character Mistake" would be the wrong category as the mistake would have been made by the set designers.
While I've never seen mislabeled items I know mistakes can happen. But since the characters aren't real, every mistake they make is the fault of someone on the crew, whether it's the actor, writer, or set designer. For example, misspellings are considered character mistakes (unless intentional), even though it would have been made by the person who created it.
Character mistake: This episode opens with James Ferris typing the final chapter of a mystery novel. He is using all-capital letters, No professional writer would do that.
Suggested correction: It's not meant to be all capital letters, but block letters. Just look at the title card and credits in the opening - they're block letters too.
A Bird in the Hand... - S11-E3
Factual error: The license plate on the automobile of Stallions football team owner Fred McBain reads STALLION1, but personalized California license plates can not have more than seven characters ( http://www.vanityplatebystate.com/alphabetical-listing-of-states/california/).
Plot hole: Jarvis Goodland, who grows orchids in a greenhouse, shoots and kills his nephew. A year earlier, Goodland had fired a shot at an intruder who was attempting to steal some orchids. The shot missed and went into the dirt of a flower pot. Columbo finds the bullet and it helps to prove Goodland killed his nephew. A bullet fired from a .32-caliber pistol would have shattered the pot.
Requiem for a Falling Star - S2-E5
Other mistake: Twice, Columbo tries to reach his wife via telephone. On the second attempt, he dials seven numbers but on his first attempt, he dials only five numbers.
Revealing mistake: In the opening scenes, it's pretty clear that the "corpse" in the bright red dress is breathing. (00:02:20)
A Deadly State of Mind - S4-E6
Continuity mistake: When Columbo asks if he can borrow the psychiatrist's lighter, the man has his cigarette in his mouth and a newspaper in his left hand as he reaches into his pocket for the lighter. In the next shot, as he hands the lighter to Columbo, the cigarette has jumped into his left hand with the newspaper. (00:27:40)
Continuity mistake: During his poolside talk with Nelson Hayward, Columbo carries a large cardboard box under one arm. His coat tail is hanging straight at his side in the master shot, but when it cuts to another angle, the coat is draped over more than half of the box. (01:15:00)
Any Old Port in a Storm - S3-E2
Audio problem: Pay phones always dropped your coin into an internal cash box when you finished your call. In the bar, Columbo makes two calls, and after the first, we hear the coin drop as it should. When he finishes the second call, we should hear that coin fall, too, but it doesn't. (00:34:05)
Character mistake: Columbo lies on Mrs. Van Wick's bed to demonstrate that she wouldn't be able to see the toy clown if the door was closed. He has his shoes on and puts them on the bedspread and never apologises for doing so. I don't think Columbo would be so inconsiderate.
Other mistake: In the cabin, Mrs. Danziger says he can pick up a pair of golf gloves in Acapulco. Golf gloves are normally sold as singles, not pairs. Very few people wear two golf gloves except in quite cold weather.
Character mistake: The crew of the ship is British. Most of them refer to Columbo as "Leftenant," but the doctor switches between "Leftenant" and "Lootenant."
Other mistake: The captain and the doctor play very fast and loose with medical records privacy, letting Columbo see them and discussing them.
Factual error: The nurse is smoking a cigarette in the sick bay. By 1975, when the show was recorded, that would not happen.
Factual error: The nurse brings Danziger a sedative and takes his blood pressure. She has her stethoscope in her ears backwards. A qualified nurse would not make that mistake. When she comes in after the murder to do it again, she has the stethoscope in correctly.
Audio problem: The clock striking wakes Columbo, and he gets out of bed. We see that he is barefoot. He takes a few steps in the barrack room, and we hear the sound he would make if he were wearing shoes. Then the sound gets louder and has an echo when we see him outdoors on the parade ground (in shoes).
