Got this issue after few weeks of usage. Phone just started to reboot randomly showing some artefacts on the screen, like white noise scramble on a tv. Did all the steps found on the internet, like app update and safe mode and all. Long story short... It was WIFI for me. As simple as that. I've pulled all the facts together and came to a conclusion that it only occured while I'm in a hotel room with a ****ty wifi, all my colleagues were mad at the quality of the internet too. So wild guess crossed my mind, since it had geographic correlation, and bam! It works fine while on lte. I know sounds to simple, but worked for me.