Manaflower: Had the same happen to me.
Tho considering I had run into other bugs that probably needed full restart anyway, I dunno if this is bad. Annoying regardless.
Edit:
Alright, this was simple.
You can recover old saves by copying contents of %LOCALAPPDATA%/Praest/Saved/SaveGames to similar folder in the game install folder.
However my old bug persists so I probably need to restart anyway.
I did that and it worked for the most part. But I have a lighting error now. It says "lighting needs to be rebuild" in the left corner of my monitor with red letters. And lighting truly is broken ingame...