Ok, the weirdest thing. In the wee small hours of this morning, we were woken from deep sleep when our Sonos suddenly switched itself on at loud volume in our bedroom.
I picked up my Sony Xperia Z2 and the touch screen was going crazy all by itself. The phone was in the Sonos app and was rapidly selecting options within the app, eg. adding tracks to my playlist, at around 2 or 3 every second - there seems to be no pattern to what it was doing. I managed to get the phone into lock screen, then just watched as the screen keep going crazy pushing various dots and patterns on my lock screen. Again, no obvious pattern - it seemed to be operating at the bottom right of the 9 dot grid.
I managed to power off the phone and this morning on power up, everything is fine.
Phone is not rooted and I do not install apps outside of Play store - so am thinking it is unlikely to be malicious, but maybe some phone fault. Had phone nearly two years without any previous issues.
Any thoughts on that the heck is going on????