When a location where a Woodland Mansion would have generated has already been visited in a pre 1.11 generated world, the locate command will still return those coordinates, even though a Mansion has never actually been generated at that location.
When a location where a Woodland Mansion would have generated has already been visited in a pre 1.11 generated world, the locate command will still return those coordinates, even though a Mansion has never actually been generated at that location.
Dylan
Jens Bergensten
Unconfirmed
Minecraft 16w39b, Minecraft 16w39c, Minecraft 16w40a
Retrieved
This is how the Minecraft engine works