Zombie Village Bug

When villages generate, there is a very low chance (2% I think?) that it will generate as a zombie village, where the doors are missing, some of the cobblestone is moss stone, and the village has zombie villagers. However, there is a bug where when zombie villages generate, they have regular zombies instead of the zombie villagers and none of the cobblestone is replaced with moss stone. I can tell it is not supposed to be this way by comparing zombie villages on Xbox to the ones on MCPE.