We're trying to get this down right now and I noticed a mention of the buff "Twilight Protection" in the patch notes for 4.0.6:
I wanted to find out more about this buff, but there seems to be very limited information on it. It doesn't even seem to appear at all in our combat logs. If anyone can tell me more about the buff, it would be greatly appreciated.
I believe that's the buff that you get when you first port down that prevents you from dying before you've fully loaded.