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: 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: 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)
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)