Revealing mistake: When Chloe and Jack are in the car she is looking at the computer on her lap. The gear shift in the car is a automatic and it shows it being in park as they are driving. (01:20:10 - 01:20:55)
The Prison Prep School Murder Case File 1 - S1-E10
Revealing mistake: When Kindaichi and Miyuki speak with Kenmochi, inspector Adechi is lurking in the background reading what turns out to be a French newspaper. At the beginning you can see its "Le Shinbun" logo on both the front and back cover, but later in the scene it has just one cover and the back page is just normal text (incidentally, the filler text is garbage; the headline says "Je vais essayer de répondre l'incident" and even breaks the words incorrectly, but you have to freeze-frame to spot this last detail). (00:17:10)
Episode #9.2 - S9-E2
Revealing mistake: Rose's newborn baby, Isabel, is suspiciously large and mature.