Calyxium

No clue, I haven't seen one either. When you disabled it, I assume you remembered to disable the patch as well? If I were you I'd try reloading it turning off one mod at a time, and I'd start with lighting/weather mods and anything else that would effect the Solstheim map. You can also try teleporting directly to places in Solstheim and see if you can get some places and not others using the coc command. I regret I don't have better advice for you, especially since it was the similarities in our mod list that let me narrow down what was causing my CTD.

I had the same issue, and it was Immersive Citizens causing the problem for me. I turned it off and can get to Solstheim without crashing now.