Forty Years from Sand Island - S3-E17
Other mistake: Hank Palmer appears in the closing credits as "Hank Sorenso", but his last name is pronounced by everyone (and logically so) as "Sorenson", and Rick says his first name is Fred. (00:31:00 - 00:48:00)
Other mistake: Marsha Mackenzie is supposed to be competent with certain aspects of men care; she comes from a wealthy family and she has been taking care of the men in her family all her life. And Magnum does show up at the Kamehameha club with a nicely done knot on his tie. When we actually see the actress tie that same not metaphorical knot though, it's very clumsy, crooked and differs in between shots (it's also done on an unbuttoned shirt).
Basket Case - S3-E14
Other mistake: During the game, Willie scores the 38-34 point according to the close-up of the electronic board, but in the wide angle when she actually shoots it, the score appears to be 30-31...from 30-30, which is odd, since it was a 2-point shot. (00:43:00)
Other mistake: During the airport reunion with father and son, there are several boxes of "Cole" brand pineapples...which are just Dole brand pineapples with masking tape put on to alter the letter D to a C. The tape came off one box revealing the original unaltered letter - you can also see it on the side of a box carried by an extra, Cole on the front, but Dole on the side. (00:43:05)
Other mistake: The supposed teen prodigy at the beginning of the episode hits the balls shot by the machine sky-high and off her right. Her coach and mum though are thoroughly impressed. (00:01:30)
Other mistake: In the study, Phyllis Reardon retorts bitterly at Magnum that he was kissing Ginger 'yesterday'. But they are staying at Robin's nest, and it's impossible that a whole afternoon and night went by without them talking about what happened - including Magnum to Higgins. And the doctor just came to give her a sedative for the shock...or an earlier day? (00:12:45)
Foiled Again - S3-E7
Other mistake: The culprit does not have wounds on their hands, but whoever tampered with the box left blood inside it. If the blood is irrelevant to the case and could have been left by Higgins, then it's unclear why it has an effect on the culprit and make them admit their guilt.
Foiled Again - S3-E7
Other mistake: At the beginning of the episode Magnum has some banter with Higgins, but also needs his help with a tie knot he's clueless about, to the point that he can't even pronounce its name and calls it "double Winslow", with Higgins promptly correcting him. And he's completely useless at doing it. However, in the previous season's episode "The Last Page", Magnum was helping Rick with his tie and giving him expert and sensible advice about it and explicitly referencing the Windsor knot, in fact discussing the merits of the half Windsor.
Past Tense - S3-E4
Other mistake: Magnum quite literally breaks into TC's office, shattering the glass with his shoe and reaching through to unlock the door. When he and Rick leave, he reaches in again and locks the door back. They get stopped by Lieutenant Yoshi Tanaka in the corridor, have a bit of banter without them touching the door, and when the policemen walk past them, they just have to push the door to open it; it's completely unlocked already. (00:15:55 - 00:16:55)
Did You See the Sun Rise? - S3-E1
Other mistake: During the opening credits, the writing "and Lance LeGault as Buck Green" appears. As shown by the name tag later in the episode, his character's last name is Greene with 3 Es. (00:06:50)
Other mistake: When Magnum is watching the game on TV, it is also the game TC is watching, which makes sense. What makes less sense is that it is also the same game, same action, that was shown just 3 episodes earlier in 4-8, when Rick and Higgins called him as he was supposedly in the Tiger Stadium with an invite for the locker rooms after. (00:17:35 - 00:34:40)
Other mistake: Rick is telling Magnum about the time he was playing stickball in Chicago. His tale is interrupted by a ball flying high for the home run. The shot, with the ball ending over the outfield fence as it falls, is a blatant recycle from the very opening of the episode; the ball that Danny was pretending to try and catch as he ran to the fence dropped from the sky with those exact same 3 utility poles, in "Taiwan." It's also a clear sky that does not match the overcast sky of the practice match. (00:02:20 - 00:24:20)
Other mistake: Forgetting the absurdity of a kid who's never been on a horse before that can just hop on one and gallop all night long, the stuntman riding Agatha's horse when Higgins and Magnum watch them fade into the night wears a striped shirt; Benny in the morning is still on the horse, on the run, but has a sports jersey with a very different color pattern, basically bi-color with the full bottom half powder blue. (00:36:50 - 00:38:15)
Other mistake: In the shots from inside the van it's easy to tell that Benny throws the newspapers in such a weak way that they hardly can reach past the outer fencing and walls - in fact the last one he throws before TC tells him "Not like that" is shown in the next shot landing on somebody's lawn, but from the van window you could see he tossed it into a driveway, at a height that could never go past the hedge. (00:32:00)
Operation: Silent Night - S4-E10
Other mistake: Higgins ask for the hacksaw from TC's toolbox. In 30 seconds sharp (no pauses in the dialogue), Rick brings it to him. So the wrecked airplane and the chopper are 10 seconds apart, in a thick forest. That's quite a bit uncanny. (00:24:15 - 00:24:45)
The Ugliest Dog in Hawaii - S1-E8
Other mistake: At the end of the episode, Zeus and Apollo are in a cage, and it is explained that it's because of sir Algernon's presence, due to Magnum's decision. It makes for a humorous finale, but does not make any sense; it's sir Algernon that has to be isolated for the 4 months quarantine, and an earlier segment implied that a fence had been built for him, as he needed to be limited in movements to avoid contact with the ocean and everyone on the estate.
Other mistake: Erin at the beginning of the episode records her acting using a camera on a fixed support. She gets interrupted once. She resumes then. The camera angle is different, and then simply changes (as it's made clear by Magnum rewatching later the actual tape) without anyone else operating the camera.
Other mistake: The photographer takes shots of the Brigadier on the balcony. The Brigadier is wearing a shirt and pants, fairly casual as expected. When Hooker is left alone in the dark room of the terrorist, he is looking at pictures of the Brigadier wearing a white jacket and bowtie, which is the outfit he will wear at the party several hours later. (00:12:30 - 00:25:35)
Other mistake: The creepy photographer guy is taking pictures throughout the episode. His camera somehow reaches everywhere on the estate; front gates, lawn, the Brigadier's balcony, with extreme close-ups and disregard to walls and structures in the way. It's one of those magic movie cameras.
Other mistake: The IRA operative puts the bomb into the Audi with a timer rigged for 5:00. Three minutes and a half of time that cannot be compressed (no cuts to any other scene that happens simultaneously - and if anything, more time than that should have realistically elapsed) pass before Magnum even gets on the Ferrari and drives out of the Nest. The way it is shown in the episode, Magnum could never make the heroic save. It gets even worse at the ending; 15 seconds remain on the timer and Magnum has yet to force the Audi down the beach road, the car has to reach the end of said road, Magnum runs, on foot, to their point, convinces them that there is indeed a bomb, and they run for cover.taking cover and waiting for the thing to explode! A minute could have been spent for that task alone. (00:39:20 - 00:42:50)