Slow Tango in South Seattle - S2-E1
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: 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.
Suggested correction: In episode 6:02, Frasier's Curse, Niles finds Frasier's head in the stove and is worried. Frasier responses "I was cleaning it, Niles. It's electric" The matches seen in episode 2:24 were more likely used for candles (like for Frasier's bath), not the oven, because it's electric.
The range is gas burning. You can see the grates and burners indicative of a gas cook-top. The comment regarding the matches wasn't used as proof the range is gas, but merely to point out they had the ability to light the gas cook-top (to avoid someone correcting the mistake by saying maybe they had no matches). The mistake is valid. In s06e02, the cook-top is still gas and one may want to submit a character mistake for that episode because Frasier says it's electric when we see it's gas. However, if one submits the mistake, be prepared for someone to correct the mistake by pointing out that dual fuel ranges exist, so the oven could be electric and cook-top gas, Frasier has an electric oven and gas stove, or Frasier was simply lying.