I've seen that this has been an issue in the past, so I managed to isolate it to me updating to 5.3.7 last night.  Attempting to play Diablo III today, my cursor would disappear after joining a game.  Uninstalled and reinstalled 5.3.5 and everything is fine again.
 
Windows 7 64-bit
2x 980ti
OSD off (though EVGA server was still running in the background on 5.3.7, this is something else I was reading was supposedly looked at in 2014)