This puzzles me so much.
I am playing as Sweden. I built up enough power to be able to bully Denmark as I please. They still have most of their 1066 territories. Then I saw that I can "Claim Denmark". Awesome, so I can get all territories at once. I declare war, I proceed kicking them around until I get 100% warscore. Time to cash in. I enforce my demands. And PUFF: not only Denmark is still independent, but it got a freaking half of my territories!
Is such a thing even possible? Or is it a bug?
I don't remember if at a time I was also King of Norway or if I already lost it for succession, but I don't know if this should influence it...