It should [citation needed] only be the VOD that get’s blocked. But there could be specific game code blocking the broadcast of the music inside the Xbox itself (so yes other people are Cap. carding)
Basically all Copyrighted music gets blocked.
So GTA Radio, Fallout 4 Radio, Rocksmith are all basically out VOD/stream Wise.
You can try Twitch Reddit for further advice -> http://reddit.com/r/Twitch