Whiterun, it's one of the cheapest if I remember correctly. I had that problem with the concentric-circle shadows in Breezehome, and also in a couple of interior shops in Solitude. I even tested the vanilla game and I get the most awful shadows only in those places.
Originally Posted by crazyeyesreaper
link to said mod ^ dont tease people with fixes and not link it hahah
It's called "Shadow Striping Fix" on the Steam Workshop. And it's created by dWILLb.