This has happened to me multiple times in a row now -- I spend effort to breed a good heir with perfectly fine traits and some good base stats, then I grant him some land to manage (so that it goes back to me when I play him and I can redistribute my demesne however needed), but within a few years he gets ultra crappy traits. I could not even possibly exaggerate what happens; it's ridiculous. He goes from having 5-6 positive traits, loses just about all of them, and gains the exact opposite traits in their place, plus some more bad traits. How does this happen? It's been 3 times in a row now. I'm beginning to simply cheat good heirs now instead of caring about breeding them, just because this is so ridiculous.