Continuity mistake: There are two mistakes in the last 3 scenes of the movie. From the moment Joe, Olivia and Finn return from the hospital, Finn and Olivia are seen sitting on the dock in the same clothes they wore earlier in the movie when Joe is cooking. Also, the next scene shows Finn going to the girl's class to speak, but then the following scene shows Finn, Olivia and Joe back at Olivia's house in the same clothes they wore home from the hospital as if it were another day referencing Finn's experience being asked about blimps.
Continuity mistake: When Fin and Joe are staying at Olivia's place after dinner and she is lying on the couch and Fin is sitting on the floor, her left knee is in front of the right knee, but when it switches to another camera, her knees are switched and depending on which camera, her knees are back and forth from different takes.
Continuity mistake: In the beginning of the movie, Fin grabs a mailbox that is on the floor of his deck outside his office and holds it up to where a dwarf would be able to reach it. He places the mailbox back on the ground and walks into the office. He then goes to the convenience store without touching the mailbox again. When he returns from the convenience store in the next scene and is talking to the hotdog vendor, the mailbox is somehow nailed into the wall where he was measuring it earlier.