The Hong Kong Kowloon Treasure Murder Case File 1 - S1-E1
Other mistake: Throughout the episode, certain street signs ("Job&Piece", "Ocean Guest House") are used multiple times in different points of Hong Kong (for instance the establishing shot of the city, behind Kindaichi and his friends when they meet, during the bike chase).
The Game Mansion Murder Case File 2 - S1-E24
Continuity mistake: When the contestant drops her ramen bowl and chopsticks, the food, the bowl and the chopsticks are in different positions throughout the rest of the scene. (00:08:00)
Inspector Kenmochi the Murderer File 4 - S1-E22
Other mistake: When Busujima tells the real story of what happened 3 years before, the bathtub in the background drained completely, but nobody removed the drain stopper, which in fact is in frame and perfectly placed. (00:10:55)
Inspector Kenmochi the Murderer File 4 - S1-E22
Other mistake: When Kindaichi shows his phone with the incriminating evidence, the phone's charge is at 60%, exactly the same charge it had last time we saw the same phone screenshot for the same purpose in the previous episode. Mere minutes later for the bathtub demonstration Miyuki calls him and the phone is charged at 80%. (00:07:50)