My G6 had done this twice in the past week. And I only know it reboot because it's asking me to enter my PIN instead of taking my fingerprint to unlock the phone. Still love the phone. Hopefully it's an isolated incident. Good thing I registered for the 2nd year warranty.
My phone just randomly rebooted
Are you within return period? Pay with a credit card 60 day purchase protection?
Return it if you can.
Return it before you lose something down the line important!