When Sharona meets up with Monk on the street, there are two cars - a dark colored car, and a gold colored car (which might be a Rolls Royce based on the the obscure view of the hood ornament) parked across the street behind her when the camera is facing her. As the camera goes back and forth between her and Monk, the gold car disappears, and reappears.
When Sharona was talking to Angie Deluca at her house, level of tea in the glasses changes between shots, alternating between full and half full.
In Mr. Monk and the Billionaire Mugger (2002) (and many others), characters will sometimes refer to a police officer as being a "second lieutenant." This rank is found only in the Armed Forces. Police departments use the rank of "lieutenant."
When Monk and Sharona try to leave in her car at Sidney Teal's mansion, the car won't start. A staff member of the mansion attempts to fix the car. At some point, the person hands the distributor cap to Sharona. A few minutes later, without installing it again, the car starts perfectly fine.
But the reason the car failed to start was because of battery, alternator, or starter motor issues. The problem had nothing to do with the distributor. The engine crank is clearly heard working very slowly when they first tried to leave.
But the reason the car failed to start was because of battery, alternator, or starter motor issues. The problem had nothing to do with the distributor. The engine crank is clearly heard working very slowly when they first tried to leave.
When the shooter from the yellow Mustang squeals away after shooting at Monk and hitting the glass panel, the right-hand windows all fully up. But he could not have shot at him unless the window was down.
When Monk prepares to pet the dog which he thinks is stuffed, the dog's ears are cocked up. When the camera switches to Monk then back to the dog, the ears are down, meaning that Monk should have known the dog was real.
When Randy has the map and puts a pin on 19th (at Guerrero) where Fraidy Cop is supposed to have flagged a taxi, you can see a pinhole there, indicating at least one previous take or rehearsal was done of the scene.
At about 36 minutes the camera pans over two patrol cars. The cars have the same unit number, 20498.
When Monk and Sharona are driving after seeing the crime scene where Modine shot Teal, Monk tells Sharona that the speed limit is 35 mph. In the background, a speed limit sign shows the limit as 50. This was shot in Oshawa, Ontario (close to Toronto), where the limit is 50 km/hr on many streets.