Young Kidaichi's Murder: File 1 - S2-E1
Other mistake: Kindaichi escapes handcuffing the detective to the toilet's chain. Try to think of the last time you went to a restroom and the chain was SO long that you could yank it across the whole room (not stall, room) and outside the door. Going behind the sink's drain, even. Never seen a toilet like this in my life (and in that kind of bathroom, you have usually buttons or pedals, anyway). (00:21:00)
Opera House Murder Case: File 2 - S1-E22
Other mistake: At the beginning of the episode, the characters are gathered thinking back about part 1 of the case. Amazingly enough, the propmaster's armpit ate the A of his shirt. Now he's not a "BADMAN", he's a "BADMN." (00:02:05)
Opera House Murder Case: File 2 - S1-E22
Continuity mistake: There's a blatant coloring error regarding Kindaichi's clothes when he speaks to the inn's manager through the window; his shirt goes from orange to lilac, with a pea green undershirt. (00:09:05)