duplicate username in confluence and ldap causes confluence to read group membership from local user instead of ldap user

Steps to reproduce:

1. create a local user (testuser) in confluence and add the user to confluence administrator-group
2. create a user with the same user name in ldap
3. Restart confluence or flush the cache
4. go to <your confluence address>/admin/users/domembersofgroupsearch.action?membersOfGroupTerm=confluence-administrator , you can see that the user (testuser) is in confluence-administrators group.
5. if you click into the testuser you'll notice the user does not belong to the confluence-administrator group (as the LDAP user does not belong to confluence administrators group).

The problem is the confluence administrators group is displaying the local user, but when you click on the user, it fetches it from LDAP. This is confusing.

If at step 3 you do not flush the confluence cache or restart, when you click into that user you will see the information for the local user instead (as it has been cached). This is expected when going through the confluence administrators group, but if you go directly via the manage users page, it will show the local users details, when you are expecting the LDAP users details.