Randomly generated Skulk vein / Atomic sized Ancient city

Not much to describe here, just some skulk veins that seems out of place. I'm not sure wether this is intended or not, or wether this issue is about randomly generated skulk vein or about atomic sized Ancient city. Either way, sorry for the inconvenience.

Seed: 7374569563155168570
Coord: Pretty sure, it's in one of the images

Tried to see through the walls to find a nearby Ancient city, only found that one chunk of skulk environment. Once again, i'm not sure wether this is intended or not.

Thanks.