Had this when the game first came out. I updated video drivers and it went away:
All NPCs displayed as large black blobs. After the drover update I happily played a fairly bug-free playthrough.
I have not played KCD for a few months. I wanted to play today. So I started the game up.
The Black Blobs are back.
I have changed nothing. Whiskey Tabgo Foxtrot, over.