Void Black Box?

Was deciding to fly above the void area on our new map, not using any mods whatsoever, and this is what I see. A rectangular blacker box that what the current void is going completely beneath me. It's not game breaking, but it is weird and was unsure if it was supposed to be like this.

Images of the black box itself.
http://puu.sh/7U8Si.jpg
http://puu.sh/7U8Th.jpg
http://puu.sh/7U8Uc.jpg

Image w/ the "Info in the left corner":
http://puu.sh/7U965.jpg

I would assume steps on recreating this would be to be in creative, and fly over a " completely " voided area.