I didn’t find anything in the list of cron jobs on that machine and WordPress did not have a plugin or a wp-cron job that indicated anything happening every 3 hours.
The guy also rambled something about our machines being seriously underprovisioned, so we allocated more memory and CPU cores for this and while it did recover quicker, it still crashed regardless of havin 16 GB of memory and 4 cores.
And it was index.php of all things that was blowing everything up every 3 hours on the hour.