In the final Bellas performance, Ashley's hairstyle changes halfway through the performance. It goes from a sleek straight style, to a more rounded, voluminous style.
As the Bella's are posing for their graduation photo Lilly has her hands on her cap when the flash effect is shown. Then, when the picture is shown Lilly has her hands in front of her in a prayer-like gesture.
In the riff-off Clay Matthews is referred to as William Clay Mathews IV when in reality he is the III.
When the girls are in Copenhagen as tourists they mention visiting Hayden Christian Andersen's house, to which Fat Amy replies that he sucked in that Star Wars movie. Should be Hans Christian Andersen, the writer of The Ugly Duckling, The Little Mermaid is who they should be referencing.
Das Sound Machine perform Bell Biv DeVoe's "Poison" during the "90's Hip Hop Jamz" battle with the Bellas. Although this song was released December 28, 1989, "Poison" rose from number fifty-two to number thirty-eight in the week of April 14, 1990 on the Billboard Hot 100 singles chart and eventually peaked at number three for four consecutive weeks, beginning on June 9, 1990. The single also peaked at number one on the Hot Black Singles chart for two weeks. It became one of the most successful singles of 1990 and was a staple on MTV and mainstream radio in the summer of 1990, spending ten weeks in the Top 10. The single peaked at number seven on the dance charts. It was certified platinum by the RIAA on June 1, 1990 for sales of over one million copies.
The coffee cups that Beca delivers at the music studio are obviously empty; they make hollow cup sounds as she places them down on the desks.
The boat that Fat Amy is "rowing" across the pond is obviously stationary and fixed in place. Her rowing motions have no effect on the boat.
Although in the original movie Aubrey erases the board containing the Bella's path to success, in this movies, when the Bellas go to first rehearsal with Emily, the board is intact. Chloe turns the board, and it reads "Das Sound Machine" on the other side.
When the Bella's pose for their graduation picture Ashley is standing beside Cynthia Rose with her arm out for the picture. When they show the picture afterwards Cynthia Rose's arm is out and Ashley is in the middle back.
The aerial shot of Copenhagen contains marks for Poland, Germany and the UK on the horizon, even though the view direction is northward. Neither Germany (~130km south), nor Poland (~230km southeast), nor the UK (~900km west) are marked correctly. If any, only the north of Scotland might be in the field of vision on the far left of this angle.
According to the dean, all of the members of the Bellas are seniors, meaning that despite being 3x defending national champions, the Bellas have added exactly zero new Bellas in the preceding 3 years and there'd be no one left remaining in the group when everyone graduates.
Throughout the film, Flo implies that she's in the U.S. illegally, but she apparently manages to fly Europe for the World Championships and returns to the U.S. for graduation without any customs or immigration problems such as leaving or re-entering the country.
Despite "sleeping on a bed of Grammys" and producing several gold records (seen on the wall at the studio office), Beca's boss is apparently clueless about producing a Christmas album for Snoop Dogg with help from junior staff and interns at the studio, yet still schedules a recording session with one of the biggest recording stars in the world without having any idea what to do.
The character of Denise from the first Pitch Perfect (2012) film is missing in the sequel and no explanation has been provided for her disappearance.
When Emily is auditioning for the Bella's she has a white bracelet on her left wrist. But around the 22:50 mark, after they say she's in, her bracelet disappears, then reappears in the next frame.
When she is apologizing for her exposure, Fat Amy's name is listed underneath her as Patricia (Fat) Amy. In the first Pitch Perfect (2012) film, Amy states that her real name is Fat Patricia, not Fat Amy, suggesting that Patricia is her real first name. The way her name is presented in this film suggests that her first name is Patricia and her last name is Amy.