Limestone Golems drop Mudstone?

As the title says, it's something that's bothered me a bit. This might have gone better in the lore section, or maybe I'm just nitpicking.

In a similar but less bothersome way, we also have Chinchilla Hides that don't come from Chinchillas, Morbol Saliva that doesn't drop from any morbol variety mob, ahriman tears, bear skin, and so on.

EDIT: I'm referring to the mobs in Churning Mists.

I think it's because the golems were in the game before we got limestone added as a crafting material. Might be completely wrong though but I do know that black limestone wasn't there when I levelled up miner in 2.3 & came later. If limestone was there then it was possibly excluded because it didn't have a use until housing arrived.