Obviously a pattern here.
After it didn't work yesterday. I deinstalled OneDrive completely from my system (including all data left in %localappdata%\Microsoft\OneDrive).
Reinstalled the version linked to by MaRoselle Cag.
Synchronizing was a pain (lots of sync errors), thus I also needed to remove data from my local client and synced from scratch.
It worked fine then for 24hrs. Then the issue appeared again. In %localappdata%\Microsoft\OneDrive there are now 4 sub folders (18.025.0204.0009 / 18.065.0329.0002 / 18.091.0506.0006 and 18.091.0506.0006_1) whereas the latter one creating the issue. The *exe can be found in both folders *006 and *006_1 but when starting manually, an error message pops up asking for a dll in *002.
As a workaround I copied the *exe into *002 folder and started the program from there. It seems to work but unsure if this a stable solution.