I had this too! Got to the bottom of it! Turns out it was Cloaks of Skyrim from oldrim!
http://www.nexusmods.com/skyrim/mods/12092/?

Such a strange bug giant paper aeroplanes that cast shadows on the ground and flicker. For me it seemed to affect my view mostly on sunnydays even when noone else was around. looking back I probably had a cloak equipped and it was nothing to do with a bad graphics card driver, corrupt file, ENB, Vivid weather mod or anything that altered the world space.

I isolated Cloaks by the long process of trial and error. I guess I'll pass it through a nif converter or wait for it to be converted for SSE.

I guess this is a perfect example of why you should only add one or two mods at a time and test as you go!

Just want to take this opportunity to say thank you So DAMN much Boris Vorontsov! Your work has really made me happy and helped give me a fantasy world to escape into when I needed it! xxx.


Have fun!