Switching to "Synchronise Group Memberships" option in the delegated user directory should push changes back to remote directory

Here is the procedure to reproduce the issue:

1. Set up fresh jira
2. Create a user A in the LDAP server which got no membership settings. (single user without group)
3. Set up delegated ldap - with only the option "copy User on Login" and set the default group member to "jira-users".
4. Login with the user A, so that it can be added in the group "jira-users".
5. Logout the user A.
6. Edit the delegated user directory and check the option "Synchronise Group Memberships".
7. Login with the user A again, we found that it is impossible to login.

Regarding to the login file, the user had been removed from the user group when login, here is an example of the message:

2012-09-27 18:39:35,327 http-6512-10 INFO anonymous 1119x482x1 1mknmyc 127.0.0.1 /rest/gadget/1.0/login [atlassian.crowd.directory.DelegatedAuthenticationDirectory] Deleted user "user"'s imported membership of remote group "jira-users" to directory "Delegated Authentication Directory".
2012-09-27 18:39:35,329 http-6512-10 INFO anonymous 1119x482x1 1mknmyc 127.0.0.1 /rest/gadget/1.0/login [atlassian.crowd.directory.DelegatedAuthenticationDirectory] Deleted user "user"'s imported membership of remote group "jira-developers" to directory "Delegated Authentication Directory".
Sep 27, 2012 6:39:35 PM com.sun.jersey.spi.container.servlet.WebComponent filterFormParameters

And we can observe the same in the user list.

So far we have been able to reproduce the bug only with OpenLDAP and Generic Directory Server.

The workaround for now would be to add the group memberships again after checking the "Synchronise Group Memberships" option.