sudo nano /usr/share/alsa-card-profile/mixer/paths/analog-output-headphones.conf
Modify the following:
; Keep Line Out disabled in the headphones path so selecting headphones
; does not also drive speaker/line outputs on shared controls.
[Element Line Out]
; switch = off
; volume = off
required-any = any
switch = mute
volume = ignore
override-map.1 = all
override-map.2 = all-left,all-right