Something Borrowed, Someone Blue (2) - S7-E24
Other mistake: When Daphne comes to the Winnebago she doesn't close the door properly, you can see it opening slightly again. When she and Niles drive off, it's closed.
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.
Answer: In the last episode, they explained that Tossed Salad and Scrambled Eggs is a metaphor for the mixed-up people to whom Frasier dispenses his radio psychiatric advice.