Apple watch won't control iPhone Audio
So I got some new BT headphones (Sony) and they pair with either my watch or my iPhone, but when I'm playing Music through the music app on my iPhone the watch doesn't show it (it says nothing is playing on the iPhone) and, of course, can't control it.
This is very odd since every other thing I pair (earpods, other BT speakers, my car BT system) allows the watch to control the audio. Any ideas on what's wrong here or how to fix it?
I originally installed the Sony apps but I figured they were the cause so I made sure I exited them. Perhaps I should completely uninstall them to be sure but I thought I'd ask here first to see if there were any other reasons the watch wouldn't be controlling what's played through the Music app on the phone.
Apple Watch Series 4, watchOS 5.0.1