Multicam audio mute on source monitor

Hi everyone!

I'm asisting in a documentary with lots of interviews which I synced/subcliped using the multicam feature but what we (the 2 editors and me) realized after a while is that some multicams don't reproduce sound when played on the source monitor. If we dragged them to any timeline or if we open them in timeline (like, opening a subclip in avid) we can hear everything perfectly. 

It's just that we can't hear them in the source monitor, which is a problem when you want to match frame and hear the rest of the interview, for example.

2 more things that may come in handy to solve the issue:

1- I tried duplicating one of the functioning multicams and replace its content with the clips (video and audio) from the wrong multicams. Loading this new multicam in the source monitor does work... But I can't automatically relink the clips from the edited timelines to these new "corrected" multicams.

If you know a way to, I'll be glad to hear so!

2- When I load the wrong multicams in the source monitor, the Audio Clip Mixer appears empty.

Last but not least, we are working with Productions. I haven't had a problem so far, but idk.

Any help/tip would be greatly appreciated !