A few months ago Windows 10 introduced update 1803, which changed the volume control for bluetooth devices. My Augustus EP650 bluetooth headphones used to have separate volume control on the desktop and on the device itself (e.g. you could make the Windows volume very loud, but the device volume very quiet, for an average final volume). After the update both volumes are now linked and change together.
This wouldn't be a problem, if the minimum volume wasn't extremely loud, the granularity decreased to 6 points, and going below 6 more often than not mutes the headphone permanently until a restart.
Searching around I found a reddit thread from around the same time, and the following comment from a Microsoft developer:
Windows bluetooth dev here - if anyone can't control their BT speaker/headphones volume from the PC after the update, can you share a product link to what device you're using? We added "absolute volume" in the last update which lets the Windows volume slider directly control the local volume of BT speakers/headphones who support it.
I have all available Windows updates and updated drivers, and the headphone works fine on my Android phone.
How do I disable this "absolute volume" feature to regain the level of control that was available before?