Moto G XT1032 - Shuts down ramdomly.

Hello,

I have a XT1032 stock with 5.1 Retail US with bootloader locked. Really stock with every OTA update.

I'm facing a problem since the last month:
The phone turns off ramdomly. It's doesn't reboot, it just turns off without makings sounds, animations or vibrations.
Ej: I use the phone, leave it on the table and when I take it again, it's off. I missed a lot of alarms because of this [emoji19]
Another thing that happens is that images or audio messages thst i took or downloaded recently are erased after it shuts down. So when I turn it on, they are gone.

What I did until now?
- 5 Factory resets.
- Changed the wall charger.
- Changed the charging method (usb, powerbank, etc).
- Used in Safe Mode.
- Used it without installing any additional application.

All this without solution!!!

I don't know what to. Can anybody help me?
Will a downgrade to 5.0.2 Retail US help? Is it possible to do this without risks with this tutorial http://forum.xda-developers.com/show...2542219&page=1 ?
It's a hardware problem?

Thanks in advance.