China Doll - S1-E3
Character mistake: As they are driving to uncle Han, Mai Ling says that 11 other members of her family might have died for the urn. Magnum speculates "Cousin Ho." But he called him "uncle Ho" in his "should have stayed in bed" voiceover at the beginning of the episode. (00:09:55 - 00:28:25)
China Doll - S1-E3
Character mistake: Rick is supposed to be at least competent in first aid, but there's a short (and awkwardly edited in) clip with TC trying to get up and groaning in pain where the taping around his torso is so loose he shouldn't have bothered at all. (00:25:10)
Thank Heaven for Little Girls and Big Ones Too - S1-E4
Character mistake: Higgins is extremely protective of any little trinket and bric-à-brac at the Estate, but in this episode he barely bats an eyelid at a post-impressionist masterpiece being handled casually, rolled up and passed around. He handles it pretty badly himself.
The Ugliest Dog in Hawaii - S1-E8
Character mistake: Steve gets on Rick's truck and tells him "Just follow that car." However, when we see what happens through TC's chopper, the van is in the lead, and the car is the one following - probably it was footage shot with the intention to reveal Magnum's plan earlier. (00:42:00 - 00:42:40)
Character mistake: Mrs. Pauley says that Magnum told her that Bobby is alive "a couple hours ago", but it was the day before. (00:42:25)
The Curse of the King Kamehameha Club - S1-E11
Character mistake: Poolside before his mysterious illness, Rick tells Magnum that the board wants to cancel the "ski surf" race. That'd be the "surf ski" race. He should know, he organizes it. (00:33:15)
Character mistake: Twirling their moustache at the success of their operation, the villains say that the heroin is worth 10 million dollars. When Rick looks at all the drugs, he says it must be worth "a couple millions."
Character mistake: The day of the race, Higgins reacts to Adelaide mentioning Norman as if it were the first time he ever heard the name, but he was present when she mentioned him, and the case. Not being all that involved, technically he didn't have to remember that, but he remembered the detail of the uncle, and forgetting that the woman was talking about someone being murdered, is quite odd - and is just done for the cheap gag that follows.
Character mistake: When Magnum parks the car in front of the Kahala Towers, the word "parks" has to be used very loosely; the car stops on the left side and at little distance from another car on the right, effectively blocking the whole road. And that is in a moment of total quiet, not rushing out of the car to save a baby or something like that. Whoever parks their car like that deserves to be shot on sight. (00:12:10)
Character mistake: Magnum and Billy Joe Bob face one of Ito's goons. The guy is supposed to be competent with nunchakus, but he simply waves it around with no skill and in the close-up of his warrior yell, he strikes a pose with it but you can see at the bottom of the frame he misses the catch and does not grab the other stick. Obviously the extra was hired simply because of the looks and ethnicity but had never used this goon's supposed weapon of choice before. (00:24:55)
Character mistake: Higgins holds his glass of brandy with Magnum's photos in the other hand and says "I don't know if you're pulling my leg, as you Yanks put it." It's really not an exclusively or typically US expression; in fact it originated in England. (00:27:35)
Character mistake: When Magnum looks at the pictures Higgins gave him, he sees one with a flare that will require him to ask Higgins to do some movie photography magic to remove it. However next to it there's a picture with just a slight less zoom that has no such flare. Magnum for no reason entirely ignores it while he only needed to grab a magnifying glass instead of begging Higgins and wait for the film to be developed again. (00:29:30)
Character mistake: Sitting at the club's beach bar, when TC urges him to give him the rest of the money Rick says "eighty" when he is in fact giving at least the 9th 10 dollars bill. (00:16:20)
Wave Goodbye - S2-E7
Character mistake: At the station after the release of the first suspect, Kelly does the good cop routine and apologizes for his Sergeant, saying he does not like a private eye telling him how to do his job. Magnum 99% of the time during the show corrects people saying "private eye" with "private investigator", but here, he does not. (00:16:20)
Wave Goodbye - S2-E7
Character mistake: At the end of the episode, the cop reads the culprit his right, twists his arm and exits stage left with him. But 'left' happens to be towards the ocean, away from the patrol car. He also leaves the gun behind, lying in the sand. Worst cop ever. (00:47:45)
The Taking of Dick McWilliams - S2-E9
Character mistake: Rick describes to his buddies the kidnapper's car as "a yellow Bronco." It's a jeep and it's orange/brown with a white roof. The description is so off that it's a miracle they found it to begin with. (00:16:10)
Character mistake: Rick reveals Magnum that a certain person committed "security fraud." That'd be securitIES fraud. (00:40:20)
Character mistake: Higgins' anecdote inflicted on Rick says that In Kwangju. In '49, Corky Boswick got kicked in the head during "Sunday of the Queen's birthday party", but at the time, George VI was still King, and would be until February of 1952. (00:42:25)