Wouldn't you know it....all of my reboots started after I upgraded the camera's firmware. Here is a time line of my NVR usage....
4/13/2017 got it up and running. Started recording 24/7 and IVS. Two reboots that day, probably on purpose although I don't remember it restarting and in the file it says the 0x00 is a Normal Reboot and the second was 0x01 which is an Abnormal Reboot.
4/14 - 4/21 NO REBOOTS (that I know of or in the log)
4/20 I upgraded the firmware of my cameras.
4/21 I somehow (I forget how) restarted the NVR on accident. Or maybe it just rebooted itself while I was on it and I thought it was something that I did. Either way, that isn't in the records log, I just remember it happening. On this day after that reboot my IVS push notifications mysteriously started working on my phone. I don't think I made any settings changes
(see here)
Then on the the 22nd which was 2 days after upgrading my camera's firmware the reboots started for me. Every day since then including once today already.
Anybody else want to check the time line of their reboots vs firmware upgrades?
It could be just a wild coincidence, but it also might explain why not every 5216 NVR owner has reboots...