Windows Sound Balance

Jatgm said:

Thanks for replying! Sadly I haven’t found a solution yet, but I contacted a Microsoft Employee and he said to check one of the updates and to do a system restore to a different update for before when it worked. I haven’t tried that yet, but it may be something that you should check out.

Lol, it's Aug 2019, and still facing this issue. Not sure if this is really a bug, or if my BT headphones don't allow for imbalanced inputs.

There is an incredible helpfull, small tool (122kb) called SimpleSndVol.
Once started, you find it in the taskbar's lower right corner. You have direct access to Left/Right balance and sound volume.
In the (many) possible settings you also find a "Start with windows" option .