For nearly a couple of months now, Nexus Player users have been reporting about an annoying issue that causes the device's remote to sleep after 5-10 minutes of inactivity. It's only after a button is pressed on the remote that it awakes, but that also includes a wait time of few seconds.
Well, the good news is that Google has identified a fix for the problem and is currently testing it internally.
So as you can see, a Google employee has revealed the issue was due to the Bluetooth nearby scanning feature that got enabled accidentally. They further added the change only requires a server side flip. We expect the change will be pushed out sooner than later.