My wife and I have identical Moto G (1st Generation) phones now both running 5.1 lollipop. My wife's has a magnetic flip cover, mine does not. My wife's phone rings only once when receiving a WhatsApp call with cover closed. Ordinary calls rings many times as you would expect. With cover open problem goes away. I've seen reports of somethings similar but relating only to when phones are in quiet, vibrate only mode - people report only one vibrate. There seems to be a solution for the vibrate issue via an App named My Vibrations, so I'm tempted to try this to see it solves rings problems too. All suggestions gratefully received.