Revealing mistake: Right after Newton drags his girlfriend to the ground and before Magnum spots him and takes aim, Eric walks at the top of the barge...but it's not the Eric we see then in close-up; it's a burlier guy dressed the same.
Audio problem: When she comes around at King Kamehameha and especially in the scene by the tidal pool, Rebecca Holden's lines are very noticeably dubbed in.
Continuity mistake: In the intro, Bobby holds Diane telling her nothing will go wrong - last famous words. Between the first shot and the close-up, her hair changes position on the shoulders, and when she hugs him, her hand is off and on his shoulder at the cut. (00:03:55)
Continuity mistake: Magnum walks up to his client, waiting on the beach in a suit. He tells him he's flattered; José Ferrer's arms are folded, at the cut they are down his side and only then he folds them. A very similar flub happens seconds later; he pulls the letter out of his pocket, and does it again in reverse shot. (00:07:05)
Visible crew/equipment: Magnum asks the judge what could that woman from 40 years ago have on him, and as he waits his answer, he looks down. His sunglasses then are tilted in a way that reflects the lights of the set. (00:08:50)
Continuity mistake: When Magnum shows Rick the picture, Rick untangles his fingers twice in the separate shots. (00:11:30)
Visible crew/equipment: Magnum is on the beach with Maku's grandaughter as they observe him swim. They are in abundant company though, as In his sunglasses there's the reflection of several people - the camera crew. (00:12:20)
Continuity mistake: After Kiki says that Maku bodysurfs "whenever he feels old", you can spot in the footage of the man in the ocean that he's wearing fins at his feet. Maku emerges from the ocean cool as a cucumber but with no fins. (00:12:50)
Continuity mistake: Shot from the waist up, Maku is wearing a bracelet on his left wrist and quite a lot of his soaking wet hair trapped under the towel he has across the shoulders. He then makes his way to his camping chair, and he has no bracelet and his hair drier and off the towel. (00:13:35)
Audio problem: When Zeus (or Apollo) drops the towel, Magnum looks at him and says "Hi guy!" in dub, but Tom Selleck's mouth is simply open as he is breathing in some air. (00:17:25)
Other mistake: In a cute scene, the lads are helping Higgins pamper Magnum for his nefarious needs. So one of them drops a dry towel for Magnum on the stone platform he uses to come out of the tidal pool. It's a nice scene, but the stone block is isolated in water thigh-deep for 6'3" tall Tom Selleck, and one the doberman has trouble getting off from - you can see him look at the trainer off camera and then do a very awkward dive at the end. So there's no way that dog could have brought Magnum a towel, at least a DRY towel. (00:17:30)
Continuity mistake: Magnum walks back from his swim and approaches Apollo (or Zeus) holding a pair of flipflops in his mouth. There's another large and smooth shadow to the left of the dog in the first shot, not making an appearance in Magnum's POV. (00:17:45)
Revealing mistake: The article Magnum reads in his Ferrari, by the title "Local judge offered high court seat" begins like this; "A former Los Angeles Veterans young actress, a bone of contention feet wide and eight feet high. Powered by electricity, it carries its own won't even pay that." Filler text can't get better than that. (00:21:25)
Continuity mistake: Judge Robert Caine comes out of the hotel while Magnum is munching Higgins' lunch and reading the articles. A couple (she wears purple) walk by him. Magnum spots him and scarfs down the last bit of the sandwich, closes the bag, starts the car; a good 30 seconds passed before he's out of of the parking lot, and yet next time the camera goes back to the judge, the couple from earlier is still passing him by. (00:21:40)
Continuity mistake: When the judge asks Magnum "Take me back to my hotel", in the background there's a woman in a blue pantsuit and there are people by a large building entrance she's approaching. Switching to another shot, and all of that is just gone. (00:24:40)
Visible crew/equipment: Driving through an alley in present day jogs the memory of Judge Caine. On the right of the frame though (and left side of the Ferrari) you can see a contraption where the camera car for the fade-out shot is mounted. (00:24:55)
Continuity mistake: During the knife fight, people appear and disappear between shots from the flight of stairs outside. (00:27:40)
Audio problem: The young judge runs away from the guy he stabbed. He promptly then tells Diane "C'mon, get in the car, c'mon." Not only is the audio of different quality and dubbed later in studio, but Miguel Ferrer's lips don't move at all for the last part. (00:28:25)
Audio problem: In the shot when Bobby and Diane drive off, the exhaust fumes show the car is turned on before the opportune sound is inserted. (00:28:25)
Continuity mistake: Rick spots Higgins at the club and tells Magnum to hurry up. He is wearing his ring and a bracelet on his right hand. When Higgins leave, it's the same, and you can even see he's wearing a watch with a leather bracelet on his left wrist. But then Magnum leaves too, and in the very last shot of the scene all the aforementioned accessories switch side. (00:29:10)
