They definitely do (there are only 2 streams), and Roku is the only platform I'm having issues with. In fact, if I back out of playing and then immediately hit play again, it will often work fine and I will get audio when it switches up to the higher bitrate stream. So sometimes it works, sometimes it doesn't.
I have the channel published as private - I can provide details if there's a way to do that and you can see if you have the same results I'm seeing here.
It's odd.