On the 360, with one of my larger save files (around 25mb) a character has the snow effect everywhere, inside, outside, on a sunny day, in Blackreach, and so on. I've tried to fix it by switching areas but all I seem to do is pick up more lighting shaders. I just used one of the black books that has the "damage in shadow" effect and now back on Solstheim I now take damage just standing around anywhere and lighting such as torches or the spell candle-light no longer negate the damage effect, great for leveling resto though!