Goof (continuity error): In the episode "Case of the Crying Comedian", actress Sue Ane Langdon is seen sitting at the bar, then she comes down the stairs and moments later is seen sitting at the bar again.
Goof (revealing mistake): In "Case of the Grinning Gorilla", you can see the flesh underneath the eyes of the actor portraying the gorilla, especially in the close-ups.
Goof (revealing mistake): When Mason introduces the "newspaper photo" as evidence, since it shows great detail and no halftone dot pattern, it is obviously not from a printed paper, but is an actual photograph.
Goof (revealing mistake): When Mrs. Adams is found dead of a heart attack, the actress playing her is obviously still breathing.
Goof (continuity error): The district attorney introduces himself to Mason as Darwin Hale, but later in his office, Betsy Burris calls him Bill Hale.
Goof (boom mic visible): The shadow of a boom mike can be seen on the wall behind the judge's box during the last ten minutes of the episode.
Goof (continuity error): The left gauge on the oxygen tanks indicates "10" when the doctor examines it, yet it indicates "2" before and after his verification.
Goof (errors made by characters, possibly deliberate errors by the filmmakers): At one point in Perry's office the real Louise refers to Myrna as Louise.
Goof (revealing mistake): Perry and Della spend the night in the lower level of a boat, supposedly alone. But when Della climbs the ladder to the deck to leave the boat, with Perry still waiting below, you can clearly hear her say softly to someone above "Excuse me."
Goof (continuity error): A janitor opens the door from the outside, he is not wearing glasses. The scene from inside the room shows the janitor now wearing glasses.
Goof (crew or equipment visible): Perry enters his office from the hallway door that Paul usually uses. As he's closing the door behind him, a hand outside the door can be clearly seen reaching for the doorknob to either close it the rest of the way or hold it closed.
Goof (continuity error): Color of unmarked police car tailing Perry Mason's car changes color from dark to light repeatedly.
Goof (errors made by characters, possibly deliberate errors by the filmmakers): As Arlene listens to the radio, the announcer erroneously states that police are searching for the murderer of Frank Ballard rather than of George Ballard.
Goof (crew or equipment visible): (at around 30 mins) As Perry and Paul Drake enter a hallway and approach a hotel room door, just before looking through a transom window, a part of the sound-man's rig is clearly visible at the bottom right for 15 seconds.
Goof (plot holes): Dave Kirby describes having steel implants as a result of reconstructive surgery. Yet after a fatal plane crash, his corpse is confused with that of Dr. Morris, who presumably had no such steel implants.
Goof (errors made by characters, possibly deliberate errors by the filmmakers): Dr. Barnes's first name in the closing credits is listed as George and Mason uses the name George once. However, in court, Hamilton Burger refers to him as Dr. Philip Barnes.
Goof (errors made by characters, possibly deliberate errors by the filmmakers): The same character Tony Davis, is called Anthony Davis in court by Hamilton Burger, and when Hamilton tells Lt. Arthur Tragg to pick him up for perjury he calls him Tony Davidson.
Goof (errors made by characters, possibly deliberate errors by the filmmakers): In an atmosphere of spit-and-polish, squared away soldiering, an army officer says something happened at "10:15 p.m." instead of "22:15 hours".
Goof (continuity error): The Corregidor money that shows up at the beginning is identified by its serial number and is unburned. Mr. Blake from the Treasury Department states that all of the stolen money that has been appearing in circulation never got near the bonfire that was used to burn $10 million before the Japanese Army invaded. But by the time the trial starts, the stolen Corregidor money is now identified by being scorched on its edges implying that it was raked out of the fire before it could be burned.
Goof (continuity error): Witness Luke Hickey's testimony is interrupted so Lt. Tragg can take the stand because he is wanted at headquarters and has to leave. When Tragg is done he does not leave the courtroom and is seen sitting there through the rest of the scene.
Goof (revealing mistake): Paul Drake buys a newspaper in the hotel lobby and sits down to read it. But when he holds it up, it is plainly a single sheet of large paper with a banner headline on one side and is blank on the other.
Goof (revealing mistake): At several points during Perry driving his car, there's no glass in the front windshield.
Goof (anachronisms): A twelve-year-old murder is committed with a Smith and Wesson Chiefs Special, a revolver not yet invented at that time.
Goof (crew or equipment visible): When George Andrews is helping Beatrice Cornell to his car after the vehicle accident, a microphone is visible at the bottom left of the screen.
Goof (revealing mistake): When the truck crashes into the car (off camera) there is a loud crashing sound, but the people walking on the street don't react to it.
Goof (miscellaneous): The character played by Jeanne Cooper is called Thelma Bell throughout this episode, but in the credits she is listed as Thelma Hill.
Goof (miscellaneous): The character played by Doreen Lang is clearly referred to as Miss Hill, but in the closing credits she is listed as Mrs. Hill.
Goof (factual errors): Sheriff Eugene Norris tells Perry Mason that Phil Beecher has stolen the "bi-monthly" payroll, when he means "bi-weekly."
Goof (factual errors): Expert witnesses repeatedly refer to .32-caliber revolver cartridges as "bullets".
Goof (continuity error): In the opening scene, Adam Thompson (Will Wright) tests a security camera, set to take a picture of anyone opening his wall safe, by opening the safe himself. At the time, he is wearing a gray tweed suit with a striped shirt. However, in the resulting picture, he is wearing a solid black suit and a plain white shirt.