All CPU cores not assigned to VM maxed out

Even after a reboot?

Yeah, if I reboot everything will be fine for a little bit and then all of a sudden that one qemu vm machine monitor process comes along and pins every core 

With VM services disabled? If yes try booting in safe mode.

I'm not sure if this is related, I've had a pretty stable box for years, I updated to 6.12.10 a few weeks ago and it seems like the server randomly rebooted on Sat early AM.  I didn't notice until today, I start a parity check today, and check back an hour later and server had rebooted again (Maybe cores pegged at 100% and overheating? ) .  Syslog doesn't persist as I don't have that enabled, so I'm kinda in the dark.  I've been running in maintenance mode for a few hours right now, I just ran htop and cores are not pegged at 100%.

seem to be getting something like this as well all was good until the last update box has been running solid for months after the last update when I restart is fine for a while when I check it again the next day I get below.