Thanks everyone, I really appreciate it. I went through reliability graph (didn’t know about that, great little tool!) and event viewer and only saw errors coming form applications as they came back up ungracefully.
In trying to troubleshoot stuff I added a second GPU card so maybe the PSU is overwhelmed at 650 Watts. I was having the same exact error before on one GPU card (which the 650 watts can handle easily) - but maybe I fixed something and overwhelmed the PSU on the other end. Time to overnight some equipment.