I decided to install the MWSE addon for the aforementioned mod, and after cleaning my save of refrnces to "Tel Uvirith, Tower Upper" in EE, when I enter the Upper tower, the lighting seems all dark and red-tinted. Any idea how I can fix this, short of starting a new game?

Are you running TLM or the TLM add-on for UL at all?

Nope, but I used to do so before I started my current PC who is experiencing this problem.

Hmm, well another thought is it could be an unlean ambi setting in the MWSE patch. Actually, since only the Upper Tower is affected, this may be the case. If you were running the TLM add-on it would have over-ridden this change and you would have never noticed it. Try cleaning the MWSE add-on with TESTool. That should fix it.

I'll make sure that's done for the non-beta version once it's released.

That did not do the trick. I am somewhat confused. Any other ideas?

Hmm...do you have Enchanted Editor installed? If you open the mod in EE and select cells, it should have AMBI listed if it's still there. I just tried cleaning my MWSE patch in TESTool, and it says it's clean, but when I open it in EE, it says the AMBI is still there. So it might need a manual cleaning with EE.

I did that, removing the reference to Tel Uvirith, Upper Tower, but the problem persists. I guess I'll just start a new game...

Yeah, I'm afraid I'm out of ideas there. If it's not the MWSE patch ambi causing the problem then it might be something else.

Oh well, c'est la vie, n'est pas?
-EDIT-
What are the default lighting values (Fog and Sunlight) for the upper tower (and the lower tower too, just in case, seeing as it seems to have the same sunlight as the upper tower atm. not ingame, just the CS)? I just looked at it in the CS and Fog is at 41/58/58 (Red/Green/Blue), Ambient is at 0/0/0 (normal I assume, while sunlight is at 26/0/0. I'll just switch it to the default and that should fix it.
-EDIT 2-
I downloaded a new esp, and the lighting values are the same as they are above. Am I the only one having this problem?

I'm not sure how many people are using the TLM add-on, which in combination with TLM might mask this problem, so I can't be sure. I've never heard of this problem before. Everything looks alright in my test games when I'm not using TLM. Aside from a cleaning of all the mods that alter Tel Uvirith using TESTool, I don't know what else could help.