Cobblestone village

A village turned to cobblestone

Steps to reproduce:

1. Kill all villagers in a village
2. Destroy most of the blocks in the village
3. Leave the village for a long time, I don't know how long, out of rendering distance
4. The village will be rebuilt all out of cobblestone, even surviving wood planks and logs.
Maybe it happened because of an update trying to fix world generation?