[Skunkworks] Websense Guru out there

Skunks, I'm having a recurring issue with Websense setup as a Proxy. The general issue is that occasionally it fails to identify the Distinguished name of a user from the Active Directory which results in a user attempting to browse being allocated the default (the most restrictive). This results in numerous calls to I.T helpdesk by very unhappy internal customers. Is there anyone who has had this issue with websense and how did you resolve it? I have googled and cant quite get a concrete solution. Anyone experienced the same. EAKM