I'll call this "resolved", not "solved". > I'll let it run for awhile before I believe that. I ran the -23- kernel for four days without issue. Then I rebooted into the previous -22- kernel, still installed. That has run for a day so far. So the problems no longer seem to be present. I don't know what caused them. Maybe it was just a burn-in issue with the power brick, the motherboard, the memory, or the NVMe SSD.