Hi Greg,
Have seen this issue with 5.2 Horizon view which was resolved with 5.3 http://kb.vmware.com/kb/2056258
There are a few tests to isolate this further
1)Does this behavior remain the same with Windows Client(To rule out Thin Clients Firmware/Client )
2)Does downgrading the agent helps ?????
3)Any Antivirus Software like Mcafee?
4)please disable “Always wait for network at computer startup and logon” under Computer Configuration/Administrative Templates/System/Logon. (Unless this is a requirement for you)