[jasminz]

I am one of the unfortunate owners of a Nexus 6P whose device was abrutely shutting down at random occasions. The phone would shut down when battery level usually was below 60% and I was out walking. At first I though it had something to do with it being cold outside (I live in Sweden) but later I proved that was not it. Phone itself has not been tampered with (running official Android, 7.1.1 OTA) and is in near mint condition with protective case used.

Anyways, I did what most people do not do and unlocked bootloader, installed TWRP and Pure Nexus Project 7.1.1 ROM and am happy to report that issue is now completely gone (I did stress-test it several times in below zero temperatures) !

So, no - it does not seem to be a hardware issue.