The ghost spider web may be affecting it. Basically if you make a long line of foundations connected, you can destroy a bunch in the middle, but the game still treats them as linked. People use this to create easy refresh threads on server. Just throwing that out there.
There are a lot of dirty buildings in Asian server # 4121, Skittering Cavern land section.
Server 3952 sobek cave no spawn base near , spider minataur no spawn, foundation placed near spawn spot.