I've been checking the texture of the villagers and I came across the fact that their head geometry looks like they have a hat, this makes sense for the farmer villagers although it doesn't for the others anymore.

Default texture:

Modified texture to see the geometry:

Steps to reproduce:

1. Get a texture to be able to visualize all the geometry of the villager (alternative open Villager geo.mcworld already includes a texture to reproduce this)
2. Summon villager

Expected result:
All villagers have a geometry according to their variant.

Observed Results:
The villagers have only one geometry causing this problem.