(Seemingly) any @e data selector that is not "type" fails to filter results; command instead ignores specified entity data.

Confirmed in 14w31a as well, though I do not see that snapshot listed as a version option.

Steps to reproduce:
1. Summon villager & zombie in hard mode.
2. Let zombie convert villager into zombie.
3. Use /kill @e[type=Zombie,IsVillager=0]
4. Both zombies die instead of only the non-villager zombie.

Also:
1. Summon villagers of multiple professions.
2. /tp @e[type=Villager,Profession=1] @p
3. All villagers are teleported to the player instead of only the single profession.