I have a freshly installed Server 2019 that randomly restarts. The event log shows an uptime event, and the next event, nine seconds later, is a bootup event. There is also a Hyper-V machine running Server 2019 that disappears after these boots. But after rebooting another time, the Hyper-V guest reappears. This is the second time I have encountered this in about a week.
Server 2019 is supported by ESX 6.0.0.