Have you checked borgbackup docs, FAQ, and open Github issues?

Yes

Is this a BUG / ISSUE report or a QUESTION?

ISSUE

Describe the problem you're observing.

I found it quite hard to find out how to use/allow spaces in --exclude-from file, one extra example in manual/help might help a lot:

No need to escape spaces

/mnt/c/System Volume Information

(not having to escape spaces is quite counterintuitive :)