The ASUS ZenFone 6 won plaudits for its almost stock Android experience, but a recent software update has been causing havoc with some handsets. According to an ASUS engineer, the update has caused some motherboards to malfunction, resulting in crashes, reboots, bootloops or dead devices.
https://www.notebookcheck.net/ASUS-issues-fatal-software-update-for-some-ZenFone-6-units-offers-motherboard-replacement-as-a-resolution.428837.0.html