Thinking about it more I'm going to say unbalanced wicking or too much in the coil (especially on one side or the other) and POSSIBLE hot spots. I am sure airflow could cause it, but frantically casting my eye BACK to the past, I see a sort of vague correlation between one side getting brown and a sort of early "splitting" in the coil, which with rayon means at least ONE part of the coil is too thick, in the coil, which can cause breakage. So I am thinking POSSIBLY that um my coil wasn't even, I had hot spots, or I did not thoroughly untwist or comb my wicking out well. I bet improper placement of the coil, like slightly crooked or slightly higher on one side or the other Underneath the coil could cause it.
With all that, it sort of sounds like I should add "planets current placement in the sky," so I will add that, too.
LOL.
Anan