Continuity mistake: During the scenes where they play Mortal Grandma (or whatever it's called), the characters' health bars don't change.
Continuity mistake: Carl tells the establishment's owner that Eddie and Waldo are under the age of twenty-one. However, in the episode "Best Years of Our Lives" (also Season 7), Waldo tells Maxine that he worked on a parade float every year in high school, which makes seven floats. If he failed three grades and started college in the previous season (with Eddie), he would be at least twenty-one years old by now - probably twenty-two.
Answer: It is said that as Steve Urkel became a more popular character on the show, Judy became less important to the storylines, plus either her or her parents were demanding more money, causing her to be removed from the show entirely.