The Prison Prep School Murder Case File 4 - S1-E13
Other mistake: Kindaichi puts on the table the map of the two buildings. The one to the right has a cutout part, but still shows as a full sheet. (00:19:00)
Episode #1.3 - S1-E3
Other mistake: The publican asks for payment for some drinks, saying "One and six, please", meaning one shilling and sixpence. The subtitles say "One-o-six, please."