I check out what's in Windows File Explorer, Disk Management and the command line (DIR C) to see if it's just some font issue.
My guess is it's some innocuous font issue but all I have are your pictures and not much else.)
The fact your PC is non-English and we know companies struggle with apps (not just Qnap) is why I don't think this is something to freak out over.
Today I wanted to start coding after a few days off.
As I started up the apps a number of firewall notifications popped up.
I ran the latest update a few days back, therefore I was not surprised about this behaviour.
But then I noticed something very strange.
The drive characters displayed in the app-paths where completely messed up, like replacements for unknown encoding.
Here is are some pictures

I am honestly worried. Does anybody know if this is just a bug or a bigger problem.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic