The same thing happens to me. However, the ENB file isn't what's affecting it, as I have a fresh install of NV and F&L, but have not installed any ENB files yet. If you have F&L setup per the guide, POCO BUENO should be the mod providing the road textures. You could try disabling the textures in MO (double-click on POCO BUENO, go to the Filetree tab, expand textures, then landscapes; I'm not sure if it is a road texture, or an asphalt texture, so I would suggest right clicking on a few at a time and selecting "hide" and checking out the texture in game). If you do this, NMC's texture for the roads will show up in game.
Alternatively, you can extract just the previous mentioned textures form NMC (or any texture mod you prefer that has these textures) and re-archive them. You can then load it as a separate mod in MO and have it overwrite POCO BUENO. Just make sure it is below POCO the ensure it overrides. This would be my preferred method, just in case it doesn't work I don't have to go into the filetree and manually unhide all of the textures.
As far as what's actually causing the outline, I'm not sure. I would guess something with the texture itself. It is hard to ignore though, it almost has a cell shader look for it, which clashes with everything else. Of course, if nothing else works, you can just download AWOP and spend all of your time underground
EDIT: I'm 75% sure the roads textures are the offender. I didn't test it out in game to verify, just opened the textures up in GIMP. I didn't notice anything strange in the textures, but I am far from a texture artist.
EDIT 2: After about an hour of testing, I'm stumped. I even looked at Vanilla NV, loaded through the exe and not MO, and the issue is still there, though not as prominent. IDK, but now I can't unsee it, so I might just stop playing NV forever.... I jest, I jest....
You can see the strange outline in all three of the textures below. The first one is with POCO, the second NMC, and the third vanilla.
Edited by DrainO, 22 June 2015 - 01:25 PM.