The bug

When mipmapping was first introduced in 1.7, it affected items as well as blocks. This no longer happens as of 1.8 (14w25a).

I can't seem to find this in the 14w25a changelog, so this may not have been intended. (https://web.archive.org/web/20140624075744/https://mojang.com/2014/06/minecraft-snapshot-14w25a-1-7-10-pre-release/)