Are there no more lab subways?

I thought of hacking a bit to get some actual flesh growths in the lab subways instead of just Cataclysm-DDA/effect_on_conditions.json at 8b678c8fbc51a9d6c762565fc8fbf9a64a90efb8 · CleverRaven/Cataclysm-DDA · GitHub

But it seems there are no more lab subways at all? When I inspect the overmap, it seems like those modular labs have eaten all the lab subways, being connected directly to the main network of tunnels. Is this intended? Is this a known issue?