EXACT SAME ISSUE! I have a Roku voice remote with a Roku stick, power and volume buttons work fine! Sometimes the other buttons work but most of the time they don't. I have to restart my Roku to use the remote EVERY TIME. It's super annoying 🤬
Sounds like she's having the same issue I'm having with my new Streaming Stick 4K. At random, the remote stops controlling everything but the TV volume. The only fix I've found for it so far is to unplug the USB from my TV to force the stick to restart but it goes right back to not responding a few hours later.
This is super annoying and I'm considering returning the device.