I posted about this issue back on 12/22 and by 4/23, the problem seemed to have been resolved. Well, the problem is back, but not as frequently. I had it occur twice on two different remotes.
Here is a link to my original post so that I do not have to post my Roku info again. I would have replied to my original post, but it seems to have been closed by the moderators.
Intermittent Remote Issues - Roku Community
I was able to get the remote working by removing the batteries, waiting 30 seconds and reinstalling. In at least one instance, I had to hit the reset button on the remote and re-pair the remote to the Roku device. When they stop working seems to have no pattern. The other night, I hit the mute button and it worked. When I went to unmute the TV, none of the buttons worked. It is disappointing that the problem has returned.