I've figured it out! Goblin Hordes

[Phagocytosis]

Well, there was this:

Goblins mobbing your town?

I was actually able to hold off something like a 10+ goblin attack on day 7. I figured I was going to get stomped on because by night 3 there hadn’t been any attacks. So I got 3 of my villagers setup as foot soldiers, built a lot of beds which brought me a 4th foot soldier via the random events, got them setup in cloth armor (easy to make) and when the attack happened I pressed “R” to have all of my villagers respond to the attack. We beat them and lost NOBODY in the process! WOO HOO!

@FiredHigh

EDIT: If you still have this save file, think you could send some villagers to explore around the area of your town? Maybe you might find some waiting for no reason?

I’ll certainly give that a go. Could be a little while before I am able to get back to it, though, between going through the bugs for what I have recorded so far in that first half hour, and life’s other responsibilities getting in the way.