I'm having the exact same issue Jason. I have Beats Studio wireless, purchased in 2014. Updater says the firmware is up to date (not sure what version I'm on, but it says firmware is up to date). Don't know how to check what version I'm on.
I have iPhone 6S Plus on 9.2.1 and nearly every time I change tracks or change the volume, the Beats disconnect. Only option is to turn off the Beats and turn on again. If I don't change the track or volume and just let it play, Beats will stay connected. Used to work fine on my previous iPhone with older iOS. So it must be a 9.2 issue.
I have seen a lot of people say that this has been resolved by a firmware update, but like you, my Beats are already up to date on the firmware (apparently!).
Would love to get this resolved, as it's pointless having wireless headphones that keep losing connection.
Please let me know if a solution is found.
Thanks mate,
Abs
*Edit* Just seen your comment about 9.3 Beta, so will give that a try and report back with the outcome...
Keep fighting the good fight!