Dynamic group resolution (labeledURI) via LDAP doesn't work

Hello there!

Nextcloud version (18.0.0)
LDAP user and group backend (1.8.0)
Operating system and version (openSUSE Leap 15.1)
Apache (Apache/2.4.33):
PHP version (PHP 7.2.5)

We are connected to our LDAP-Server for user-authentication and group resolution. While we’ve got no issues with the users (we log in with those), recently (since the upgrade to 18.0.0) the group resolution stopped working correctly.

On our LDAP-server we use a labeledURI to define the group members dynamically and it does work, it definitely resolves the right members when we check that (e.g. with Apache Directory Studio).

When we check the groups and it’s members on the Nextcloud-web-GUI, it does not resolve these groups right. Everyone seems to be a member there and it seems like it’s an issue with the used subqueries, but we’re not sure…

Our queries look like this:

It did work when we used Nextcloud 16.x with the exact same settings, but anyway, we already had problems in earlier versions (11 or 12).

We guess, this is a bug, since we didn’t change any settings. Are the developers aware of this or do we miss something on our end?

Thank you very much in advance,
& best regards