The Ashley's are seen in a different class, but they were always in Miss Grotkey's class.
In this episode, all of the Ashleys are in Miss Furley's class; yet in the rest of the series, all of them or half of them are in Miss Grotke's class. In many episodes, only Ashley Q. and Ashley T. are in her class.
In the episode "Swing on Thru to the Other Side", Vince says "The kids in Miss Furley's class said she (Swinger Girl) never showed up for school today". However, in this episode, Swinger Girl is ready to beat the Ashleys in Miss Grotke's (the gang's) class, meaning she is not in her class.
During the scene where the pyramid of cans falls, some scenes of the cans falling and the kids running away are played twice and in reverse. Moreover, when the cans fall, and Miss Grotke jumps off of the stage, she's wearing her usual outfit instead of the Native American outfit she wears for most of the episode.