I have the same problem, loading screens and the map flickers like crazy.
Turned on WaitBusyRenderer in ENB which causes a loss of 8-10 fps. Nothing else has any impact on it whatsoever. I tried like 100 different things the last 5 hours messing with nvidia drivers, settings, enb settings like vsync, ambiant occlusion resolution scale, enhancing game AA with nvidia AA 4x (this has been known to help with flickering trees and foliage in Fallout 4. etc, i mean im not gonna list everything i tried.. This does not occur with Skyrim vanilla and any enb I've ever tried.
edit: to be clear, WaitBusyRenderer does resolve the problem entirely, but then causes another far worse (the huge fps loss).