Sync Journal not recognized

Hi,
I use nextcloudcmd to syncronize a specific folder from a Windows Server to a Nextcloud 17.0.7 Instance. so far it works, but every run of nextcloudcmd is treated as the first run:

06-29 11:15:01:286 [ info nextcloud.sync.engine ]:    New sync (no sync journal exists)
06-29 11:15:01:286 [ info nextcloud.sync.engine ]:    "Using Qt 5.12.5 SSL library OpenSSL 1.1.1d  10 Sep 2019 on Windows Server 2012 R2 (6.3)"
06-29 11:15:01:302 [ info nextcloud.sync.database ]:    sqlite3 version "3.24.0"
06-29 11:15:01:302 [ info nextcloud.sync.database ]:    sqlite3 journal_mode= "wal"
06-29 11:15:01:302 [ info nextcloud.sync.database ]: possibleUpgradeFromMirall_1_5 detected!
06-29 11:15:01:317 [ info nextcloud.sync.database ]:    Forcing remote re-discovery by deleting folder Etags

A Sync Database is created. Really banging my head on this one. Permissions, different Path on the same Server,…, all OK. The issue seem to occur only in this specific path:
D:**************\Büro\System\Konfiguratoren\Niederlassungen.
Tested a different Path on the same Server also with an Umlaut - all OK.

any ideas?
Thanks,juergen