Keying of my CB does not override the music (radio or whatever is playing through the USB).....can still here music through the headphones. Have you encountered and resolved this? If so, how did you do it?
Turn the CB off and then turn it on again. That should work. The latest update seems to have caused this quirk. If the CB is on when the radio is turned on or the bike is started the CB will not interrupt the music. If you turn the CB on after the radio is turned on things should work correctly. Hope this helps.