Thank you but I can't be sure it's the Mojo. I know first time it happened three times within about ten minutes and I was pressing the volume buttons. Still doesn't mean it's the mojo. Could be JRiver.
What had happened was, when it was new, the 'up volume' was sticking on. I had a few emergency shut-offs with the power button. After a day or two this fixed itself. Testing it had resolved itself, I was then just gently pressing the 'up and down volume' buttons. The sound simply stopped. It happened about three times in about ten minutes, and I had to reboot Mojo each time. Hasn't happened since.
Other two times not related to this first (triple) occurance, I wasn't pressing anything. It happened about three days ago. Since I have been running only Media Go to try decide if it's JRiver.
It's why I was asking in case anyone else had difinitive answer that JRiver does that.