I have a question about DLU.

In my environment Iím running ZCM 10.3 on a SLES 10 server with all of the latest patches, ZCM is connecting back to a SQL 2005 enterprise server and I have setup 3 user sources that are all working fine.

Ok, my question is what would cause DLU to work sometime, but not reliably? I have a lab of approx. 60 workstations, every day random machines prompt for workstation credentials. I can not find any pattern as to what would cause this Ė Iím curious if there could be a bug or if I have something setup wrong. The DLU policy is assigned to the users (as part of a group). I appreciate any thoughts or suggestions!