I have been noticing that occasionally I have no navigation guidance audio and have to quit and restart Waze to restore it. The only thing I can correlate it with is another application (like iCal) shoving a notification onto the screen. When I clear the iCal alert, the Waze sound does not return. The Device Volume setting remains at max but there is no sound irrespective of whether I wiggle the setting or not.

Anybody else seeing a problem like this? I searched for a match in the Forums but came up with nothing.