Player Heads not showing skin in player but they do as a block.

So, I just updated Minecraft to 1.7.7 because i was going to play on a personal server that i updated to 1.7.7 too, so I entered and all the player head like ''MHF_Herobrine'' on any other ones don't appear with the skin of the player when worn, but when I place them as a block on the ground, they appear with it, this maybe a bug in the update or maybe is because they changed the names of the MHF's player heads.