What did I even..?

That happens with all the flooring that you have outside -- I have wood flooring next to my barn and coop (to keep the grass away from the doorway so I can get in/out easier) and I'll occasionally get a piece of wood floor when I'm in the mines on a stormy day, or a piece of stone floor from my furnace area.

 

I had this happen when my baby was supposed to be born during a festival.. I lost my baby..

 

As for an update on my end. The second-second child Abby asked me about also never appeared. I kept waiting around for her, cause i didnt know exactly how long it took for the baby to arrive, but one night in Spring Year 3 she asked again if we should adopt.

So there's some lingering trouble with this glitch, and according to what Chaos said, it might be a bigger problem.