Plugin not finding groups in FreeIPA
The plugin is not able to find the groups in FreeIPA, the reason I can find is that it is not doing the group lookup authenticated (anonymous bind). It is using the authentication for looking up users though
It should use the credentials that are used for the username-search for the group-lookup as well. So when your LDAP_URI has a username and a password configured that user should be used for the group-lookup. When the LDAP-URI uses an anonymous bind then that is used for the groups as well…
Would you mind providing a bit of your configuration so that I can create a test to reproduce the issue?

This is working config for Freeipa