It was an adult mod, but I may have spoken too soon, as it pop up again multiple times. I've done the 50-50 method several times now, gotten down to the mod, taken it out, a couple hours later the issue comes up again. Now it's come up again and I haven't added any new mods since I took out what seemed to be the culprit last night. :/
Update: @crinrict So it's the strangest thing --- I thought maybe the problem was that I simply had too many items in my mods folder. I went through, cleaned out a bunch I wasn't using, and that seemed to fix it. So, to test it out, I reloaded the adult mod I originally thought was the problem (I assumed it must have been something else, since I had deleted it before and the issue was still coming up). Well, bad idea, that started the problem again. Okay, I figured, at least now I know what it is. Surely the cause and the effect is obvious here. Not so much. Deleting the mod again, deleting the cache, repairing and updating the game -- absolutely no difference. I'm no computer whiz, but part of me thinks surely, if there was no problem, you add in ONE mod, a problem appears, then deleting that mod would logically remove the issue. So the bug persists, I have no idea why and I'm very confused.
(Posts merged by CM)