M8 Shutdown problem

Hi
I got a problem with my M8. It shuts down by it self when after some time in sleep. It doesn't happen every time after sleep, bu eventually it will shut down. The phone has never shut down while I have been using it, just after when i put it in sleep.

With my old (original) battery, I could not turn it on again before i connected a cable or recharged my battery. I thought the problem was the battery, and I ordered a new one. Today the new battery came, but the problem still continues. But I don't have to connect a cable or recharge the battery to get it to power again.

I had the same problem for about a year ago. I left my phone for a half a year, and when I then started to use it again, the phone worked for some months without any problem.

I have tried many different firmwares, also Android. The problem is still there. I hope someone knows whats wrong, or have an idea.

Thanks in advance

I have the same problem here, and is very anoying.
And i don't know how to solve...
I never will buy a Meizu again, have a lot of troubles...bizarre bugs.
My M8 turn off when the battery stay on 10%, but the meter is tottaly crazy! Oscilate a lot! Never show the real state of battery..
And when i receive a call, he turns off, and i can hang up ! This is a fucking shit
I'm are hating this phone because this, don't have an decent battery, the firmware don't work with the battery, the meter never is correct, and a lot of times just turn off my phone when i will hang up...

PLUS: He never shows my contacts! Show just the number! Amazing! Incredible! It's Meizu... Only in Meizu i have to put my contry code, my area code, just to see the name of my contact..KKK
I always have to use M8Notify, because the amazing meizu os generate byself a lot of trash process, and every time i turn on i have to clean it. Oo.

I'M ARE HATING THIS PHONE! I will change him as soon is possible.