Well, wouldn't you know it, it STOPPED. Right after I posted this, it just stopped. After a week of annoyance.... it just went away. If it happens again, I will post, but for now...
I don't get it...
EDIT: here's 4 since my last post: 3 expired and 1 invalid. I wonder why they started showing up several days ago. Has the entire internet ran out of valid certificates on the same day?