Blocks above "Y" 64 on super flat (or maybe others, haven't tried) go invisible

I was testing fall damage and other damage on a super flat, so I made a pillar to die from a high place. I then realized that when I started placing the blocks above "y" 64, they went invisible like the new barrier blocks. But they are able to be mined. It does it with any of the blocks. Don't know how you could fix it, but I hope you do.