This happens every time I hit the voice search button. I sometimes hit that button by mistake. When I press it many of the buttons stop working. Including pause/play, fast forward & rewind, back, home, mute, volume up and volume down. (There might be other buttons that don't work - I haven't tested everything.)
In order to get the remote to work again I need to: unplug the power from the roku and remove the batteries from the remote, which usually fixes it.
some similar posts talk about some of the buttons not working, but it's not the same scenario. The answer for those posts describe essentially what I do, but the problem is absolutely a bug and not at all acceptable.
I still have a couple days left on my 30-day trial and will need to return this if it's not fixable.