When I mute an audio track in a multiCAM it also disables the track video. Likewise, if I disable a track video, it disables the track audio as well. The icons do not operate independently.
It can be seen on the edit and cut pages.
It works correctly on a simple timeline with one A/V track.
One of the reasons I advocate keeping all usable audio out of the Multicam. Add it separately under the Multicam clip and actually Disable the audio from the Multicam.
My Biases:
You NEED training. You NEED a desktop. You NEED a calibrated (non-computer) display.