This has been problem for long time, probably always. ima switch to usb audio
Other note:
because killing pulseAudio is a pain,
An easier way to test on GNOME if you already know alsa is the problem is:
GNOME - All Settings - Sound, on Output tab select Headphones, click Test Speakers, click Front Left
- this is the pulseAudio test which is going to be as mono-broken as the asla test since it relies on alsa
Does not work
This has been problem for long time, probably always. ima switch to usb audio
Other note:
because killing pulseAudio is a pain,
An easier way to test on GNOME if you already know alsa is the problem is:
GNOME - All Settings - Sound, on Output tab select Headphones, click Test Speakers, click Front Left
- this is the pulseAudio test which is going to be as mono-broken as the asla test since it relies on alsa