We have had a RDS session host running 2012 R2 for just over a year with no issues what so ever. Around the July timeframe we started to see issues where occasionally a session would connect and while the mouse pointer would move the mouse clicks and keyboard input was ignored but only after the session desktop loaded. The only thing I have found to resolve the issue is to restart the server. When this occurs it seems to occur for any new sessions. I do not know if it also affects established sessions as our usage of the session host is very low over the summer.
Now that we are starting up our fall semester were getting reports almost daily of this occurring and we have been restarting the server daily as a result. I took a quick scan over the last few pages of questions in the forum and didnt see anything that stood out as someone else having this issue so I figured I would start a topic to see if anyone had any ideas what might be going on or if someone had this issue and got it resolved.