When Carrie pulls off the chicken-suit hood from Teddy, she does so twice.
The entire plot depends on the conceit that Teddy must attend night classes before he can take his GED exam. Georgia (like many, though not all, U.S. states) does not require students to take any classes before being eligible to take the high school equivalency exam.
During the classroom introduction scene, the same clip of Jaylen greeting the class is cut between other scenes 2 times, both when it's not his turn.
When Teddy and his classmates are sneaking in the Principal's office, Teddy says to Theresa she needs to stall the principal, but she thought she needed to flirt with him. She then starts talking about hearing a guy saying "I'm gonna crack that up like a walnut.", but her mouth actually says "...crack that butt like a walnut.", which was used in the trailer.
Schools usually have security cameras. "Piedmont" must not because if they did, the night school students would have been caught sneaking into the school sooner or later.
The principal puts the school on lock down. Which means all exits can't be open . If that is true then how is the door to the roof which would be considered an exit can be opened.
Carrie farts on Teddy in the hexagon. Teddy remarks about the smell. Carrie replies it is a gas: methane. Methane is a component of farts, but is in fact odorless. The gas that makes farts smell is hydrogen sulfide. She teaches chemistry, as seen on the whiteboard, so she should know this.
There is an entire scene at the start of the film at the dinner table when Teddy's sister and father tell him that standardized tests give you 400 points for writing your legal name on the test, yet when he takes the GED, you see him type his nickname in the cover page.
Teddy refers to the classroom whiteboard as a blackboard.