Ben Ritter

I have tested it, and I can happily say this is no longer a concern for Minecraft 1.8.1, running on a 64-bit Java on Ubuntu 14.04
🙂

@ Jaqi Hegland
That's not the leaves turning blue. That's the leaves being transparent looking at them but the game not rendering any blocks behind it because it knows it's supposed to be opaque. Thus, you get the blue world background behind it.

Can confirm is still an issue in 14w27b.

The game renders the leaf blocks themselves as their partial transparent versions but does not render the blocks behind the leaves as if on some level it knows it's not supposed to be transparent.
The game changes them to be non-transparent when I enter within 12 blocks horizontally of the chunk they are in and changes them to transparent when I am 16 blocks away or more. This means that if I enter within 12 blocks of a chunk containing leaf blocks, they will become opaque and will stay opaque until I leave 16 blocks away from that chunk, and they will stay transparent until I enter 12 blocks away from that chunk (in other words, there's a 4 block buffer where the leaf blocks are whatever they were last).

This will also cause you to die if you do this when mobs are tracking you. They will all hit you at once. Can confirm with great dismay.