Continuity mistake: During this whole episode, Jake calls his mother's boyfriend Greg. But in the 4th season when Judith is marrying the guy, he is called Herb. We know that it is not two different people because they both have the last name Melneck, and they are both Jake's pediatrician.
Other mistake: In this episode it's shown that Charlie can hear Alan's adventures in the bedroom. However, Charlie's room is up 2 flights of stairs and Alan's is down a hallway away from the stairs. (00:02:45)Ssiscool