Not sure if this is a bug or not, something is certainly wrong that doesn't happen (has never happened) outside of MB - I cannot reproduce it...
anyhow. I do a lot of work between my DAW and MB, and a couple times my headphones output noise instead of the audio stream. The audio is working thru my speakers but comes out of the headphones as pure static. At this point I can try another player and it's all good, so that's what clued me to ASIO, it's apparently the reason.