Automatic user synchronization from a remote directory (when a Synchronisation Interval is set) stops working when manual Synchronisation is run.

Steps to Reproduce

1. Configure a remote directory (Crowd or LDAP)
2. Define a Synchronisation Interval (e.g. 5 minutes).
3. Check it is running according to schedule.
4. Click Synchronise now.

   2015-05-01 23:03:18,358 INFO [scheduler_Worker-8] [atlassian.crowd.directory.DbCachingRemoteDirectory] synchroniseCache FULL synchronisation complete for directory [ 98306 ] in [ 201ms ]
   

5. Wait for the Synchronisation Interval again. It won't run.

Workaround

To have it working again, it is necessary to Edit the User Directory and set the Synchronisation Interval again.