Tavis: Yes and yes. And if i turn it on again it reappears.
Two screenshots in my mine from almost the same position. I can reproduce both views repeatedly by moving one tile forwards/backwards. So the chunk appears/disappears depending on my position
It seems to me this bug could be an issue in the code that considers which chunk is 'visible'/suitable for rendering
EDIT: this is reproduceable on SMP even after quiting and reopening the world. I have a savegame if someone is interested
Tavis: See MC-3998 for screenshots with debug. Apart from the visual change nothing else is affected: It is instant without hiccups or slowness