Plot hole: In the first arrest scene Jenko (played by Channing Tatum) fails to read the suspect his Miranda Rights and the suspect is later released because of this. Miranda Rights are not read upon arrest nor do they have to be unless the arresting officer is questioning the suspect about an offense. Miranda Rights are more often read during an interview if the crime is that serious but in this instance (possession of controlled substances) the suspect would have most likely been handed over to a patrol unit with a vehicle and taken to jail without being questioned, at least by the arresting officers.
21 Jump Street (2012)
2 plot holes
Directed by: Chris Miller, Phil Lord
Starring: Channing Tatum, Ice Cube, Jonah Hill, Brie Larson
Continuity mistake: When Jenko and Schmidt are throwing the house party, Jenko invited the 3 nerds to help him hack Erik's phone. When Jenko lets them in, only two guys walk in, then he shuts the door. In the next shot, all 3 guys are inside.
Captain Dickson: You are here because you some Justin Beaver, Molly Cyrus lookin' motherfuckers. You will be going in as undercover high school students.
Trivia: Before the One Percenter leader crashes his motor cycle into the chicken truck during the car chase sequence, the Wilhelm scream can be heard.