It is. What sort of problems is it causing? The two that I can forsee are:
1. People leaving disconnected sessions running and taking up resources.
2. People disconnecting and then when they connect again they get a new session, meaning that they have two sessions running.
Both can be fixed by changing the Terminal Server Configuration. On the Sessions tab, check the box that says "Override user settings" and then change the "End a disconnected session:" drop-down to something like 5 minutes. Then if they hit the "X" to disconnect their session will be logged off 5 minutes later. If users have connectivity issues you might need to set this a little higher, but usually you can reconnect in under 5 minutes.
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CompTIA A+, Network+, Server+, Security+
MCP, MCSA 2003