Audio problem: When Frasier is in the hall explaining to Kenny and Gil why Poppy has her own show, we can see Poppy through the glass of the door. She is supposed to be doing her show, and we can hear the audio in the background. However, it is obvious that Poppy is not talking at all - she is sitting perfectly still with a very blank look on her face.
Audio problem: After Mary says "Except I bet you didn't walk through a metal detector to get to class", Frasier in that shot does not move his mouth in line with the dialog that he speaks, but instead appears to be laughing. Additionally in the next shot, although his mouth now matches his dialog, he is half way out of his seat despite being sat in it in the previous shot.