[nemothekid]

>where I'm using bluetooth headphones, take the headphones off and put them back on, and music.app automatically opens and comes to the foreground of my desktop

I think your bluetooth headphones are sending a play command to your device when it's connected. I'm sure it's annoying, but I think your macbook is doing the right thing here.

[kitsunesoba]

I’m almost positive that this is what’s happening. With a pair of Sony XM3’s and various Apple devices I’ve never seen this behavior.

[nacs]

> your bluetooth headphones are sending a play command to your device

Yep this is what's happening. I have a car bluetooth addon that I purchased that does the same thing -- it sends Play commands to the phone on-connect repeatedly until something starts playing.

By default the phone will open Apple Music but if I already had been playing music on the Spotify app, it'll just start playing that instead.