I figured out what was causing it. It only seems to appear when the render distance is low.
Here's a picture anyway.
Quote from themcking
Whoa, whoa, whoa. I don't think the devs are gonna be able to add the nether AND the end in one update. (I know you said you only speculate that) maybe the nether by 1.0.0 or later, but the end? A long time from now, maybe 1.3 beta or something like that
Quote from Ender
I wish you could've been here when we were waiting for furnaces
Quote from Leftypower123
Don't ask me, ask the big bang which caused the world to form that way (ie the terrain generator)
Quote from Fiti99
that sunset its a test, tommaso said he waa experimenting with day/night cycles in creative but it will not be in 0.8