Port hangs on Portserver II after Windows 2003 sp1 installed

We have a Portserver II that worked fine until we installed SP1 on our Windows Server 2003. Now a port will randomly hang for no reason. We can logout that user from another terminal and then the port is fine. We have two different Portservers connected to our network and it happens to both about 4 or 5 times a day.

Did some setting change when SP1 installed?