The War (1) - S7-E15
Continuity mistake: After Rachel sprays water all over Cory, the amount of wetness on his shirt varies throughout the scene. (00:05:53 - 00:09:05)
The War (1) - S7-E15
Continuity mistake: When the show starts, Angela and Shawn are kissing. The shot changes to Topanga and Cory, who has popcorn on his shirt. The shot goes back to Shawn and Angela, when Cory is shown again, the popcorn is gone. Again the shot changes to Shawn and Angela, then back to Cory and the popcorn reappears.
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.