I’ve had this issue for about a week. When I play music from YouTube, the music is pretty low, I have to turn it up to 100 to listen to it which is annoying because the ads are normal volume so it blasts through my speakers when they come on. I’ve played other videos and they’re normal volume, it is literally only music that plays the volume super low. I’ve restarted my Roku, deleted the YouTube channel and re-downloaded it, but the issue still persists.
I experienced this issue and my Roku sound leveling was already disabled. My issue was experienced most often with movies on YouTube. I found that my YouTube player settings had Dolby Digital 5. 1 surround enabled even though I was only using only the TV speakers. I disabled 5.1 surround in YouTube by pressing the Up button and selecting the gear and disabling 5.1 and it fixed the movie playback.