When the girls are kidnapped, the black Mercedes Bus is initially clearly shown with a French format number plate for the Alpes Maritimes department in the south of France (CZ-081-GZ). However a few seconds later we see the number plate has changed to a different number (RY62DFD) with the department badge missing. RY62DFD is rather oddly a UK format number plate.
Aubrey continues to state through the movies that her father is in the Army. In the credits scenes when her father does show up he is wearing the Air Force Dress Blues uniform.
When Fat Amy meets her dad in the market in France he is not wearing a hat when first seen then is wearing a hat when they hug.
When the girls start a fire in the suite by accidentally knocking down the candles the smoke from the fire activated all the sprinklers in the suite remember it takes heat to activate a fire sprinkler not smoke and fire sprinklers do not all go off at once.
In the passport scene, Florencia Fuentes' Guatemalan passport, while reasonably similar -but not identical- to the actual model, includes two grammar mistakes: the issuing Authority is listed as "Repiblica de Guatemala". The correct Spanish word for Republic is "República". The date of birth contracts the month to AUG in the Spanish side, but the actual abbreviation is AGO, from Spanish AGOsto. There is also no reference to the year of birth, probably the most important part of the DOB. The rest of the words in Spanish do not include accent marks, that would not be omitted in the actual passport.
In Beca's final performance, she has a microphone. She pulls the Bellas up on stage with her. None of them were expecting to perform with her and therefore do not have a microphone. Beca sings into her microphone during her entire performance and even points her microphone toward Fat Amy when she is pulling her up toward the stage. The other Bellas can be heard perfectly despite not wearing microphones and there being no other microphones on the stage.
The category for round 2 of the riff-off is "Artists you didn't know were Jewish". Each team should have been eliminated since they sang songs by artists they knew were Jewish. It is an unwinnable category.
During the Bella performance of Cheap Thrills, you can see two quick glimpses of some of the Bellas wearing sailor hats.
In a brief flashback to Fat Amy's youth, she is wearing a My Little Pony shirt. But this shirt has the modern "Friendship Is Magic" versions of the characters; that generation of the franchise would not debut until many years after Fat Amy was a little girl.
There are no whale sharks at the Brooklyn Aquarium.
The Spanish registered Silver Mercedes Sprinter that drops the Bellas off at the Spanish hotel is in fact a US model Sprinter. European Sprinters don't have the door badges. This one is badged '2500'
Aubrey's dad shows up at the ONE performance the Bellas were explicitly NOT going to perform at before an impromptu invite to perform.
When showing Fat Amy's passport, it shows her name as Patricia Hobart, but at the bottom of the passport it says Patrice.