Project variable not working in some areas

Hello all,

I really like using QElectrotech, but I came across a little problem with project variables.
In the folio properties I added the %revision to the Rev Index field, so I can set the revision to all folios at the same time, this is required for my project. This part works, changes to this variable in the project properties show up on my folio.
I also added this variable to my filename field, but it doenst show up on my folio.
This means the project variable does work; it shows up in the Rev index field, but weirdly enough, it doesn't work in the filename field. Oh and removing the ".pdf" doesnt solve the problem

I've added screenshots to clearify my problem.

Am I doing something wrong here? Thank you in advance!

Kind regards, Mees