Lovey's Secret Admirer - S3-E19
Other mistake: At the end of the episode when Gilligan is using the lie detector he says "I love spinach." The lie detector said it was a lie. But in the episode "Pass the vegetables please" spinach is his favorite vegetable.
Chosen answer: It looks like a mistake to me I see it when the Professor is put into a trance, but it is not there later.
Bowling255 ★