The Bad Beginning: Part One - S1-E1
Revealing mistake: Near the end of the episode when the Baudelaires are in bed, the camera goes outside and pans down the front of the house. Once it reaches the next set of windows below the Baudelaires' "bedroom", the camera wobbles slightly.
Revealing mistake: When Andi walks into the library (this is not Andi's dream) it cuts to the librarian sitting at her desk and we can see the shot is flipped - note the bookcase and the librarian's buttons. (00:10:40)