Hi Jermemy
Are you able to update presence at all? In the zone where the movi users are registering what is the authentication level?
If its happening frequently, a netlog 2 from the VCS when it happens would probably give the answer or on X7.x system loglevel "debug" from the diagnostic page. It might be hard to get the messages though if it can take long to reproduce and these log should not run for a long time due to the VCS disk space.
/Magnus