As Eddie is eating the paté, the plate goes from empty to half full in between shots.
In the Veterinarian scenes as the register nurse departs with her monkey, she grabs its cage. For the remainder of the scene, the cage appears and disappears several times between shots.
In season 10, episode 8 "Rooms with a View" When Daphne is walking past the room where she has her second baby, Niles is holding their first child who is a girl. In this episode their first child is shown to be a boy.
While Niles (David Hyde Pierce) & Daphne (Jane Leeves) are kissing on the balcony, there is a camera change. When this happens Niles hands change positions.
Frasier says it's a one-hour flight from Seattle to San Francisco. At over 800 miles, any commercial flight would take considerably longer than that.
When the band is playing "They Can't Take That Away From Me," the song changes chords and notes, but the pianist's hands do not move accordingly.
Frasier was supposed to be headed for San Francisco but when the plane lands the pilot says "Welcome to Chicago"