Thanks for your suggestion (trying different codes, using the TV's original remote to "skip" previously-tried codes that proved to be incorrect). I had the same problem described in this thread: I had a Roku Enhanced Remote (for a Streaming Stick+) that I was using with a Panasonic TV. When I originally paired the remote with the Roku and the TV, it worked fine (POWER ON/OFF, VOLUME UP/DOWN). However, recently, I used the remote with another TV, and when I went to re-pair it with the Panasonic, the POWER ON, VOLUME UP/DOWN functions worked, but not POWER OFF!
I thought I had tried everything, when I came across your suggestion. I tried it and (luckily) I hit paydirt on Code 6 (better than 47, eh?). Now the control works properly again, controlling the POWER ON/OFF and VOLUME UP/DOWN functions as it should.
I have this same issue and I know my TV is compatible with Roku. It has worked fine for several months and all of a sudden the volume up button pauses the playback. Sometimes when the TV is on and I press the power button to turn the TV off it will also pause the playback. This is really irritating!