This is still an issue, I was building a rollercoaster in a superflat world with big setpieces the rollercoaster goes through. One of these is in a very large dark room but the bug makes it look like there is sunlight inside. I made a video of the room and bug: http://www.youtube.com/watch?v=4UBPaK6oFsk
It really sucks and i put such effort building this room only to find this damn bug.
A big room I built with the bug.