On 14w30b when turning my head I sometimes see the blue blankness at the edges as if the rendering of the chunks unloaded too early. It's a part of the screen that wouldn't be there at all at FOV 70 or higher.

I'd love to provide a screenshot but it's so momentary (0.5 seconds?) and only happens every one out of 20 times (total guess on that number). Someone with video recording software could probably capture it by recording for 30 seconds at FOV 60 and turning their head a lot while walking around. I was on a plains looking for sheep as part of my Day 1 ritual on a new map when I noticed it.