In the lesson "Passer un exam vs to pass an exam" it says

"To say that you passed an exam, you would use "réussir (à) un exam/ obtenir un exam / avoir un exam"

and give the example:

"Et l'exam que tu as passé le mois dernier? - Hélas, je ne l'ai pas eu / je ne l'ai pas réussi!

What about the exam you took last month? - Unfortunately, I didn't pass. (it)"

but in the writing challenge "My cousin plays the accordion" I was marked wrong for answering

"but she passed it"

with

"mais elle l'a réussi"

where it wanted

"mais elle l'a eu".

Why was that? Aren't both equally valid?

Expecially since, in the context, it was just one exam ("un examen"), not the entire degree course.

In (Australian) English we would say "I passed (or succeeded in) my final exam" but "I got (or obtained) my xxx degree".