Group folder configuration deletes content of folder

The level is Nextcloud 18 on Fedora 32. The configuration is 3 users including admin and 2 groups. The first user, client, synced the nextcloud directory with the server as group1. That user, via the web interface, tired to add the second users group to the uploaded directories. The result was the original data was destroyed. The directories were deleted and recreated empty.
What is the system state?
What will happen if I resync the data from the first client as part of group1? Will it be visible from the second group1 user member?

Now you are opening another group folder thing?

Link to other one Totally stuck sharing directories between users via group configuration

This is a separate issue. The group app appears to be deleting user data.

The web interface shows the group directories as empty. However the data is still in the files folder.
I tried to resync. That failed after several GB upload It erased several GB from the source.
This is all disturbing.


it works reliable here for years with 20 users.

The webserver has log files.
Nextcloud server has log files.
Please check them

What do you mean with “resync”? Syncing with the desktop client? Please describe more in detail.

How did you “upload”?