I had this problem too. charged to 100% in the night before and when I wake up in the morning, I realized my phone was dead. I tried charging it and powering it up with no luck. Finally, I removed the battery and place it back and it was able to power up. After which I did a master reset and keep my apps installed at a minimum (Whatsapp, Chrome, Facebook). I am still monitoring. This could be a software issue. So far no shutdowns yet. Hope more will contribute to the symptoms to this issue.
Thanks
Hope it stays ok too. It could be apps or hardware. But I'm more incline to think it's hardware. What I had installed on my INO 2 is only about half of my INO one. Never encounter any shutdown on the INO one.
Get us all posted on any issues ok? Thanks