This happens on an asus zenbook flip s ux370u.
I tried a few things but none worked, plus most of solutions are for previous versions of ubuntu which used different bluetooth services.
So i tried to install more recent version of bluez from ppa found here
but nothing changed on that, i still can't find the headphones and an output option in sound settings even though they're connected. Here what i can see from terminal:
Device 00:00:00:00:41:1F Connected: yes
[CHG] Device 00:00:00:00:41:1F Connected: no
[CHG] Device 00:00:00:00:41:1F Class: 0x00240404
[CHG] Device 00:00:00:00:41:1F Icon: audio-card
[CHG] Device 00:00:00:00:41:1F Connected: yes
Any help is appreciated, thanks!