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)
Factual error: Columbo solves the case based on fingerprints on the shell casings in the gun. No gun, even a prop gun that never fires live rounds, would be put away loaded.
Other mistake: We see Fowler (Shatner) take the gun from the board in the Gun Room. Later, he puts the gun back, but in a different place on the board. Anyone in the Prop Department might notice that the gun had been moved.
Continuity mistake: When Fowler (Shatner) goes into the Wardrobe Department and takes the parka and ski mask, he has a dark green garbage bag. When he leaves that room and goes to the Gun Room, the bag is grey.
Continuity mistake: Columbo tells Montoya he has to be back in Los Angeles on Monday. Then he tells Sanchez he has to be there on Tuesday.
Murder, a Self Portrait - S9-E1
Character mistake: When Columbo is asking Barsini about one particular artist paintbrush, Barsini says it is a fluffy sable brush. It's actually one made from pig bristle. Natural sable brushes are soft red fur, while pig bristles are stiffer and a light beige color. There's no mistaking the two, and any experienced artist knows the difference.
Character mistake: When Lee Grant cuts the reel-to-reel tape at the point after her husband says, "They've got me," she actually cuts the tape on the wrong side of the recorder. Her cut would probably have destroyed the section she's trying to capture. (00:01:17)
Other mistake: Columbo never told the character Graham McVeigh that he was sick from clams. When Columbo came to the horse track to talk to him about the case, McVeigh said to Columbo "not more clams?" when Columbo said he was sick again.
Visible crew/equipment: When Fortelli threatens Graham, Fortelli says, "I don't want the money; I want the farm," and just as he adds, "I'll see you at 6:00 tomorrow night," we can see the reflection of the moving boom pole/mic on the vehicle's window. (01:02:50)
Visible crew/equipment: After Columbo searches the victim's car and has Brindle bag a few things, Columbo heads out with his bottle of Pepto Bismol. It then cuts to Graham at the stables, and as he and Pat turn left, we can see the reflection of the lighting scrim on the door's glass windows. (00:24:15)
Visible crew/equipment: At the start, while Graham is driving he makes a right turn, and as the van passes the camera, the reflection of the scrim diffuser, etc, is visible on the van's surface and windows. (00:00:20)
