Since upgrade weird random-strings as usernames instead of Name or Email... LDAP config?

Hi,

I am running Nextcloud 20.0.10
and authoring users via LDAP.

During a recent upgrade something very strange happened:
All my usernames got replaced by random strings, so my users can not longer find each other via name or email address when sharing.

In my user list, Display Name and Email are correct, but Username is a weird string of shape xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx

So my questions are:

1 - What is going wrong with the configuration? (I assume it has something to do with the LDAP-config)

2 - How do I proceed to fix this problem without loosing my User-LDAP mapping?

Thanks in advance for any ideas … :smiley: