One of the village town square pieces generates path blocks under cobblestone, which isn't normally possible.
Process of how to repeat:
1. Create a new world, preferably a Buffet Plains or a Superflat Plains world.
2. Find a village with the classic well town square.
3. Done.
First screenshot is in a buffet world. Second is in a superflat world.
This also happens with hay bales in plains villages.