ADDITIONALLY I just figured that for the specified user (above, ABC),
a file scan:
php occ files:scan ABC
results in 0 Folders / 0 Files / ElapsedTime 00:00:00 !!!
But there are for sure a lot of files owned by this user (and beeing shown in the users Folders & WebGui)
also a lot beeing successfully shared with other users…
Scans for other users show correct files/folders etc…
I’M getting more and more LOST…