I just checked in the CS, in case it might be a dirty ref, but that book is not marked as changed in the current released version of Uvirith's Legacy, or any version for that matter. It has to be some other plugin causing that problem, because UL itself does not change that book. None of the other plug-ins related to UL have that book marked as changed either, and neither does Books of Vvardenfell, because that only adds new books and doesn't change any old ones. The Book Jackets add-on is the only one that alters that book in any way, and it's meant to be loaded with Book Jackets, which also alters that book in the same way, but has the necessary resource files included.
And what do you mean by "before"? What mods do you have loaded when you're getting the error marker? Did you save a game with the Book Jackets add-on loaded? Do you mean after?
This is a hard one to crack, but if I are correct about this there is 9 plugins and 1 esm in some way related to that book. Like you said about the UL Book Jackets Add-on plugin any of the other mods could alter that book colour after all.
Here is those I mentioned in short form:
- Book Rotate.esm
- Book Jackets (3 esp)
- Book Rotate - Morrowind v1.1
- Book Rotate - Tribunal v5.3
- Book Rotate - Bloomoon v5.3
- Book Jackets - (3 esp) - BookRotate
I mean before I activated the UL Book Jackets Add-on, the error markers I've noticed is after the Book Rotate - Morrowind v1.1 plugins activation though. :shrug:
One thing I almost certain about it's that some other books seems also have the error marker as well, my ref is for the Vvardenfell Fauna in Mournhold and Alchemy Compendium Volumes except for one volume though. I gonna try to reinstall some meshes to see if that helps. I will keep you updated about this.