Chiming in with my findings. Stuff that's probably been said before but eh. Had this bug for some time, found this thread a while back and read that SkyUI 2.2 might be the culprit so I disabled it. The problem instantly disappeared. I didn't switch to QD inventory or any other UI mods, just the Vanilla UI and Skyhud. Re enabled Skyui a few days ago, problem came back within an hour or two of gameplay, diabled it again, problem went away until today when I tried SkyUI yet again and the problem came back in about an hour. I am using the DLL loader alongside the Achievement enabler and Skill uncapper. Maybe it's the combination of SkyUI and the DLL loader? Somehow.