Zombie Villagers are named as normal zombies

That's normal. They are still zombie villagers.

I think this is due to zombie villagers having the same entity ID as zombies, but confirmed.

Same ID, read on here: http://www.minecraftwiki.net/wiki/Zombie

I am afraid this is not a issue, villager zombies don't have a number or name code to summon one (this is proof) is to type /summon Zombie ~ ~ ~ {IsVillager: 1} not /summon VillagerZombie