If a new arrow or scatter tower is built in an area enhanced by a masonry, kaboomery, battle drum, and spyglass tower, the new tower does not convert to stone. I can't tell if it's just the render that's affected or if the tower durability is also affected. This occurs in both Campaign and VS. If I remove the spyglass tower the affected towers still don't convert to stone unless they are removed and rebuilt. Then the spyglass tower can be rebuilt and the towers will remain as stone.