If I don't move my mouse after restarting and the computer sleeps the monitor (so restart then get up and leave to do something else), then I get the same issue. Luckily, I have only found that it happens in this one case. After starting/restarting, I start task manager (with hide on minimize option set) then minimize it so I can see it running in notifications area. Just doing that will prevent the issue from happening for me.
What AMD drivers are you using?