Revealing mistake: One of the party guests opens the door of the fridge and you can see behind the set instead of looking into the fridge. (00:32:40)
Revealing mistake: TC runs into Higgins avoiding him in the front view with John Hillerman, and hitting him when he's replaced by a stuntman. He also is sprawled face down on the lawn with one or both arms up. (00:02:45)
The Case of the Red-Faced Thespian - S4-E12
Revealing mistake: In the climax of the episode, Magnum tackles Higgins to the ground - but it's an obvious stunt double. (00:45:10)
The Case of the Red-Faced Thespian - S4-E12
Revealing mistake: During the attempt to Higgins' life, a knife gets stuck into a tree. It hits exactly the spot where a notch was visible already. After a cut to people running scared in every direction, the tree is again shown, and the knife is now stuck in another spot. (00:31:50)
The Case of the Red-Faced Thespian - S4-E12
Revealing mistake: After the first performance of "Sir Fearing Pangborn", the Douglas Fairbanks and John Barrymore impersonators do another spot of dueling. The railing to the right of the stairs wobbles significantly when touched, certainly not the kind of build for a luxury home like Robin Masters', but rather a stage's. (00:12:30)
The Case of the Red-Faced Thespian - S4-E12
Revealing mistake: Magnum arrives at the Nest. He opens the door and moves past two swashbucklers to talk with the person playing the piano. Is he really playing the piano, though? Apparently not, because the instrument is open and you can see that the inside does not move at all. (00:07:00)
Revealing mistake: In the night shootout, Magnum cocks his pistol in a close-up that is obvious performed by a trained stunt double. Whoever is doing this is wearing the same clothes Magnum has but with the T-shirt in pristine condition straight from the washing machine, while Tom Selleck just took a dive in the dirt. Moreover, he wears the team ring upside-down. (00:22:50)
Revealing mistake: In the opening of the second third of the season (the one with the iconic Mike Post theme) there is a brief scene with a car propelled in the air by an explosion. It's an outtake from the pilot movie, since the banged up car is very recognizable, but it's also easy to see why it was an outtake; you can easily see cables used to make the car fly in the air. Also, that car was not in an explosion in that episode.
Revealing mistake: In the final car chase, the military police radios for reinforcement; in the exterior shot that follows the one inside the limo with Rick on his back, foot on the cockpit, you can see quite distinctly the two stuntmen meant to be Magnum and Rick, and totally not looking like them. (00:46:30)
Revealing mistake: The prince and TC's protege have a fight when the spoiled kid is eliminated. They are supposed to be angry and serious, and the teammates too have worried faces, but in the shot when TC tells him that he's out of the game, against any logic the young actors are caught laughing. (00:23:20)
Legend of the Lost Art - S8-E10
Revealing mistake: In the cave, after Magnum bangs on the ground the hidden door opens, and when he lights another torch flame, the end of the cave set is visible at the right side of the screen. Also, in the previous shot Magnum is not wearing his watch when the door opens, then it suddenly appears on his wrist when he crawls through the doorway. (00:03:45)
Revealing mistake: When TC and Bryant leave Agent Estin's office it cuts to TC's van on the highway, and as we hear Magnum in the voiceover talking about his dad's advice, "to call the monsters out," we can see the shadow of the helicopter filming this footage. (00:08:20)
Revealing mistake: During Magnum and TC's dive in Kahuku Lagoon, while they're underwater the windows of the tank enclosure are visible in a few shots. Also note, at the start of Magnum's daydream dive, we can also see people behind the windows. (00:05:10 - 00:09:00)
Under World - S5-E5
Revealing mistake: In the opening shots of TC's helicopter, in one shot there are two helicopter shadows being cast on the water below, one shadow is TC's chopper and the other shadow is the filming chopper. The helicopter also changes between the T-tailed, Y-tailed, and different type skids. (00:01:30)
The Eighth Part of the Village - S3-E3
Revealing mistake: When Sato arrives at the estate he exits the car then walks with his two guards towards Higgins, and in the wide shot as Higgins and Sato face each other for the first time, note all the small branches strategically placed on the grass to mark the four actors' proper positions for blocking the shot. (00:41:20)
Revealing mistake: When TC, Rick, and Higgins rescue Magnum and JL in the chopper, TC is wearing a short sleeve light blue tee shirt, but once they take off with Magnum hanging onto the side of the chopper, in Magnum's closeup TC is wearing a yellow tee shirt. Also note, the pilot in this shot is wearing dark brown spandex-type long sleeves under his short sleeved yellow tee shirt, to give the appearance of being the same skin color as TC. (00:39:20)
Revealing mistake: When Magnum chases after Randolph at the airport tarmac and finally catches him, there's an outline of elbow pads on Magnum's sleeves. Earlier, there was a shot from behind Magnum as he pulled the gun from his waistband, and his sleeves were normal.
Revealing mistake: At the King Kamehameha Club, while Joan Gibson is sitting at the table, there are at least two wires crudely attached to the bottom of the tablecloth preventing the wind from blowing it upward, and disrupting filming of the outdoor scene.
Revealing mistake: In the opening shot, while Carol Ann is calmly jogging, moving along right beside her is the filming vehicle's shadow, visible at the bottom of the screen, then Carol Ann exits the park. (00:01:30)
