Discovered a bug (Browser --> Chrome - latest version).

Mute all sounds -- > sound is muted
In settings:

All sounds are muted:

Bug:

Adjust volume level (in case sound comes on too loud). Sounds are then activated (even though all sounds are muted).

Work around:
Deselect 'mute all', reselect 'mute all'.

If volume setting is modified again - repeat above work around to re-mute.