Other mistake: When the power outage occurs, Daphne claims she can't cook the steaks, however, the cook top in the kitchen is gas. They have matches as shown by them lighting the hurricane lamps.
Other mistake: When Frasier sets off the fire alarm Daphne comes running from her bedroom at the end of the hall across from Martin's room and Frasier's room. That is incorrect and impossible since Daphne's Room is on the other end of the condo and separated by the balcony. Given the condo layout, it is impossible for Daphne's bedroom to have a door across from Frasier's bedroom.
Other mistake: When Frasier enters the apartment, Martin and Sherry are talking in the kitchen. If you listen carefully to what they're saying, their conversation makes no sense. Martin says something along the lines of "Daphne is really a very nice girl" before suddenly, in a very different tone of voice, he says "You're right, we're not getting enough privacy around here". Seems like a big chunk of conversation was edited out.
Other mistake: This is for the episode "Crock Tales" (the 22nd of the season). Almost all the flashback sequences are wrong in time. The one from 2003 has Niles and Daphne coming back from their honeymoon but they married in 2002. Although not ever couple take their honeymoon directly after they've married, the wedding episode "Ring Cycle" mentions them going on their honeymoon.
Other mistake: When Frasier is complaining that he is not mentioned in the acknowledgments of the novel, he picks up the book and then slams it down on the desk. It sits face up, near the front of the desk. In the next shot of the desk, we see that the book is face down and has moved back.
Other mistake: In the kitchen, when Niles burns his hand you can see him move his hand down to stop the frying pan from falling off the stove. He doesn't touch it again, but it looks like the instinctive actions of someone who knocked something over rather than part of the scene. He just slips out of character for a moment.
Other mistake: Frasier seems jealous in this episode that Dr Webber went to Oxford, he even says, "Oh well, even better," in comparison to his own Harvard. However, in several other episodes we are told that Frasier got degrees from both Harvard and Oxford so why the jealously? Similarly in other episodes, he never mentions Oxford, only Harvard as where he went to University.
Other mistake: About 2/3s of the way through the episode, Daphne and her ex-boyfriend are at the courthouse where he is getting married. There is a board in the background with the names of the judges listed on it. The bottom judge's name has the "u" missing in the title Judge.
Other mistake: In the scene where Frasier is in line for tickets for Roz he is talking to Lana on the phone and asks if he can move Kirby's tutoring up "tomorrow" to four right after school because he made plans with Claire later that night. You can see on the sign next to him that the tickets go on sale Saturday morning and Roz had previously said in the beginning of the episode that she wanted to start standing in line Friday so she would be first in line Saturday morning. So it is obvious that Frasier is in line Friday night which would mean tomorrow would be Saturday, which means Kirby being in high school would not have school the next day (Saturday) like Frasier said. (00:21:05)