Hi,

press NAV in the bottom line menu to go to the Navigation home screen


on the NAV home screen, there´s a bubble with 3 dots left bottom corner.

Press this, and you are on the NAV settings screen, the mouth should be in the bottom right corner. Press it to mute / unmute

Thanks Mike
I had already managed to clear it but I'm not sure how. I still haven't found the mouth but I'll check it out next time.
Thanks again.

Might be you have to adjust the loudness level when it´s "on".
Could also be you need to be in "routing" mode to be able do do that.
My wife had a similar problem and "somehow" got it fixed. I think we now have it under control....