I caught the 'indeterminate' style progress bar searching for devices when the audio glitched, so hypothesis is confirmed re: the cause. I also tried a few more.devices: my wife's tchotchke wireless speaker and a set of ear defender type headphones for noisy.work environments. Same issue each time, so I can't blame the other hardware. Never have been able to play audio on car stereo. Local audio goes silent, but doesn't switch to car. But that's another problem for another day .

ed. spelling