Sync doesn't work after file version restore

I have a problem, that after I reverted some documents (which magically got 0KB size) that the new version won’t be synced via my nextcloud client to my OpenSUSE desktop.
Even if I hit force sync. I’ve also scanned this directory with the occ command.

Has anyone an idea what’s the problem?

Nextcloud Client: 2.5.3-lp151.2.3.1 (installed through main suse repo)
Nextcloud Server: 18.0.4 (recently updated from 17)
OpenSUSE: 15.1
File Encryption: no
Storage: local