Whatever it is, it didn't happen with the 10/31 build or anything before.
[Update]
OK. This is starting to get weird. I just tried out the new Dec. 11th build... well, the debug actually, as Avast recently cleared it, and found all lighting normal. I was about to jump for joy, but I felt I should do a bit more testing first. I loaded up the Dec. 06th build again, release version, and again it was black except for the glowmap. Then, I loaded up the Dec. 06th debug build and lo and behold, it was back to normal lightning. Something in the release builds is killing ambient lighting, but the debug builds don't.
[Update 2]
Now this is pissing me off. I just loaded up FS2+MPV2014, and its giving me the no-light routine now. I even loaded up under the Dec. 06th and now the Dec.11th builds, and both are giving just glowmaps. This problem is irritating because the behavior is changing.