After the Jaguar is pushed into the canyon, it comes to rest with minor damage. When Columbo inspects it the next morning, it has much more damage: the front bumper is missing, the headlight assembly is gone, and the body has more front end damage.
After Columbo stumbles down the steep slope, the cigar he managed to maintain in his right hand on the way down begins switching hands as cameras change. It even disappears entirely, though briefly, when he digs out a bullet from the crashed Jaguar, with his mouth and both of his hands visible and cigar-less.
When Columbo is talking to Jarvis Goodland in the latter's pool room, the position of the balls on the table changes noticeably between the first view of the table and the view just as/before Columbo starts shooting balls.
When Cathy Goodland gets the telephone call from "kidnapper" Jarvis Goodland, the bedside nightstand photo of her husband is turned toward her. Only its edge is visible, propped against the clock radio. Cathy gets up to find that her husband indeed is missing. When she returns to her bedroom, the camera pans across her nightstand to show that the photo of Tony is now turned around 90 degrees, facing toward the camera. Also, the photo has moved over to the far side of the clock radio.
When Columbo and Wilson are examining the yellow Jaguar, Wilson holds Columbo's raincoat over his right arm, while Columbo digs the bullet from the seat. The raincoat is visible in the full-length shot, but it disappears in the reverse shot, when he is writing on the envelope he put the bullet in.
When Jarvis and Tony are working out the kidnapping details, Tony is listening to the police dispatcher on his radio. A closeup shows the "police radio" is just a common portable AM radio that would not receive police frequencies. At one time, LAPD (and other police agencies) broadcast on frequencies in the AM band and could sometimes be picked up by commercial radios, and some radios had provisions to tune in on AM police bands. Though by the time this was filmed, LAPD probably had stopped using those frequencies.
In one scene near the middle when he's talking to Ray Miland in the solarium, Columbo mentions a RED Jaguar but it's obviously a yellow one that went over the cliff.
Maybe this scene was shot first when they were still using a red Jag.
When the sergeant is explaining to Columbo that Tony was shot at close range and there were powder burns, that wouldn't be true because Tony was standing halfway across the room from Jarvis who was just inside the doorway when he fired.
The base of the bullet embedded in the seat of the Jaguar is actually the base of a center fire casing, not the slug. It is shiny brass and the small central cap can be clearly seen. The shell casing is not fired from the gun, but remains behind either in the cylinder of a revolver or ejected from a semi-automatic.
Jarvis kills Tony with a self-loading pistol. However, when the gun is fired, the slide does not move and no casing is ejected.
When Jarvis is delivering the ransom money and Columbo is tailing him, they turn on to the main street where a Bank of America is on that corner. After they have driven a short way, Jarvis notices in his rear-view mirror that Columbo is tailing him and there is another BoA sign reversed in the mirror since it's a reflection and behind him. It is too close to be the first BoA sign that was on the corner from before, and it's on the right side of the road, but there is yet another BoA sign on the left of the road at the same time ahead of him to the left and not reversed as it's not a reflection. With some of the other signs visible in both areas, it would seem they just reversed the same area to use for a mirror image.
After Jarvis drops off the money, he drives a little way around the corner and stops again, but Jarvis is out of focus and the grass on the other side of the car is in focus.
At 34 minutes the pursuing police car has a red light on the roof on the passenger side. In successive scenes, it shifts between the driver's and passenger's sides. This is because the video of the police car was mistakenly reversed for the rear-view mirror shots.
As Jarvis was driving away after the ransom drop, an electrical cable for lighting equipment can be seen laid across the dirt road.
Columbo is supposed to be very observant and into details, yet when Tony's body is discovered, Columbo doesn't notice that Tony is wearing the same clothes as the masked man who picked up the ransom from Jarvis.