I have been facing the same issue in my setup.
however i figured it out by following two options.
First i edit the LDAP configuration and it seems that users get updated, their group memberships seems to be same and they can join chatrooms as well. ( I have mapped the chatrooms with AD grops and is set to members-only.) group membership updated after i edit the LDAP config.
but my Roster which is also mapped with sahred group seems not to be working fine. i tried alot but Roster still remain the same (unchanged) however in user group membership it shows the correct group membership.
Last resort! which worked for me for everything, right from user updation, group membership, Roster listing, shared group all set good and updated by only restarting the openfire service.