Plot hole: At the beginning of the episode, Eric and Jack call the cops on Luther for planning an illegal rave at the college, but the cops let him go because he had not started the rave. He still broke into the student union building, and therefore should have still been arrested. He even threatens Eric and Jack afterwards right in front of the cops, and they do nothing about it. (00:00:20 - 00:02:10)
The Witches of Pennbrook - S5-E5
Plot hole: In this episode Cory takes Topanga on her "first airplane ride". But in season three (episode 66), Topanga had to go Disney World and she obviously took a plane.
Truth and Consequences - S3-E7
Plot hole: In this episode, it is discovered through a scientific study that Eric does not dream, and in fact doesn't even register brain activity while he is sleeping. However, the season 2 episode "Wrong Side of the Tracks" features a subplot where Eric listens to a motivational tape while he sleeps so he can learn to ice skate, and he dreams of Nancy Kerrigan giving him a lesson.
Plot hole: After Shawn leaves Cory's house to get a pizza, he calls Cory on the phone literally a minute later to tell him that Lenny Dykstra is at the pizza place. There's no way Shawn could have left Cory's house, walked to the pizza place, spotted Dykstra and either asked to use the restaurant's phone or found a pay phone to call Cory in such a short amount of time. (00:13:30 - 00:14:45)
Chosen answer: In the present day, with the United States abiding by more stricter school health laws, for the most part this wouldn't be in school cafeterias as many cannot even have carbonated beverage machines now. However, in the 90s when the show takes place, it wasn't unheard of for there to be coffee machines in the cafeteria of small schools where the teachers eat with the students as we see them do often in the show. The idea being that the cafeteria was small enough so a teacher or hall monitor could catch a student before they could drink the coffee.