Bluetooth header/speaker control fixed in Mobile Insider Preview 14393.105.

[Captain_Eric]

I'll need to test this more in the coming days, but it looks like the music control on Band 2 is working smoothly when connected to a Bluetooth earbuds or speaker. Previously, you needed to follow a "work around" sequence: connect the Band 2 to the phone, then launch Groove Music, then connect a Bluetooth device.

 

[Captain_Eric]

Nope. Not working, at least not once today, which is too many times. Must following the work around sequence to control Groove, etc. volume, pause/play, next/back track from Band 2.