Came across a weird issue at one of my customers recently where RDP connections would randomly (or so it seemed) drop when users were working on remote machines. They are using Configuration Manager 2012 and have client settings setup so that Remote Control is enabled on all clients. After seeing this post by Wes Kroesbergen and this forum post initiated by Wes, we discovered that this was happening for us as well. The problem is that fDenyTSConnections is set to 1 (disabled) on the clients by default, so when machines update Group Policy settings it will use this setting instead of the ConfigMgr client settings and drop connections for a short time even though you have enabled this in the ConfigMgr client.
If you are encountering the same issue it can be reproduced by running a Group Policy update (gpupdate /force) and your RDP session will promptly get disconnected.
The fix for this issue, then, is simply to set the fDenyTSConnections registry key to 0 to enable RDP connections by default. Of course you have to apply it to the appropriate computers.
The key can be found in HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlTerminal Server