XP GPO RDP idle time out not working

We have an XP VM, that is part of our domain, and there are a few users that RDP to it.  This is the policy that is set for the idle time out and disconnect timeout

Windows Components/Remote Desktop Services/Remote Desktop Session Host/Session Time Limits
Policy Setting Winning GPO 
Set time limit for active but idle Remote Desktop Services sessions Enabled Remote Workstation Idle Policy 
Idle session limit: 1 hour 
 
Policy Setting Winning GPO 
Set time limit for disconnected sessions Enabled Remote Workstation Disconnect Policy 
End a disconnected session 10 minutes 
 
Policy Setting Winning GPO 
Terminate session when time limits are reached Enabled Remote Workstation Disconnect Policy 

However, we have discovered that a user isn't logged out of the system if they are idle for 1 hour (currently there is a user logged into the system who hasn't been at work for 4 hours, but is still logged into that XP box). 

Any help would be appreciated.

(P.S. our domain controllers are windows 2008 R2)