The Hong Kong Kowloon Treasure Murder Case File 3 - S1-E3
Plot hole: The surprise reveal of the killer doesn't make any sense, because Kindaichi gathered everyone involved in the case, and the killer very much is; they are absent for no reason, so the denouement shouldn't have even started and the audience would have to be napping not to notice.
The Hong Kong Kowloon Treasure Murder Case File 3 - S1-E3
Other mistake: Saki was filming the table from his seat, and he couldn't have got close-ups of the soup bowls from the angle proposed. (00:04:45)