Starring: Taiki Matsuno, Emi Uwagawa, Kazuyuki Aijima
Yukiyasha Legend Murder Case: File 1 - S2-E14
Other mistake: Throughout the whole three-parter, whenever the characters are in the snow, it comes down at really sharp (45°) angle with a whistling wind, but their hair and clothes are entirely unperturbed.
Wax Doll Castle Murder Case: File 2 - S1-E8
Character mistake: Hajime's proposed solution is obviously wrong, but not for the reason they mention; the 'killer' could never clean themselves up completely and effortlessly in such a short time from the soot.