Attached you will find the syslog from my box. From what it looks like the CPU overheated and then perhaps some threads crash, but someone with more experience here take a look and tell me what you think. The crashes seem to be random, and I can experience 1 a day or multiples, it varies. They do appear to be load related as the more activity the machine sees the more likely it is to crash. I've recently added the LetsEncrypt docker and started using Nginx to reverse proxy all of my other containers so I don't have to punch a bunch of holes in my firewall for remote access. Before LetsEncrypt was added the last docker added was Plex which I planned to try out before making the switch from using raw file shares w/ a Kodi PC connecting back from another room.
I'm running 6.5.3 Basic on a i7-3770S CPU w/ 24GB of memory, and 16 TB across 4 disks, no cache drive. The machine is headless, so I cannot provide what was on the display at the time of the event(s). I tried plugging up a monitor after the fact over HDMI but the machine didn't recognize it and no signal was being sent to the monitor. Perhaps I should temporarily keep a monitor on the floor beside it until this is resolved (unless there's enough info in the syslog and diag dump)?
I've also attached a diagnostic report that comes from my box AFTER restarting it since it can't be gathered during the crash event. I'm happy to provide any additional information requested to help figure out why this keeps happening, so don't hesitate to ask.
syslog-1533257925
unraid-diagnostics-20180803-1158.zip