BluegelMarius -
Is it possible that your config has a role search base defined and your role(s) fall outside the search base? For example if you have this config:
roleSearchBase: ou=orgunit,dc=acme,dc=org
and your LDAP user has:
memberOf: cn=role1,dc=acme,dc=org
the role will not be returned in 8.3 as it falls outside the role search base.