Alas, around 60 hours in I am starting to see the same problem.
It is clearly related to visiting a spot more than once.
I removed the root, and the glow remains. Forever.
We're all going to start seeing these nirnroots from hell.
It's clearly an issue related to playtime.
LAUGH AT ME NOW, SUFFER WITH ME LATER

My nirnroots are practically supernova's
now. I use them as guide posts for waterways in the wild. Just imagine if Skyrim was real life! With these nirns no one would ever fail to find water in the wild. Heck, even in the daylight it is like having mini suns flare up from the ground.
