My Motorola Z3 keeps shutting off. I have reviewed the posts from many of the users who have the same issue. So, let me short cut some of the questions.
1. It does it at any power level.
2. It does it in safe mode.
3. I am running the most current version of software.
4. I have rebooted my phone twice now. I have not downloaded any apps, and I have removed all non-essential apps that came pre-installed.
5. Purchased the phone new in Aug 2018.
6. There is no damage to the phone.