I'm seeing the same issue on the 1.18.2 version of the mod on my server. Initially I thought there might be some chance that these underground villages spawn deserted, which I thought was a cool touch. However, I've visited 5 of them at this point and all of them are devoid of villagers. Standard above ground villages are appropriately populated.

The mod appears to work fine, though, in a single player game. If there are any logs I can provide that can help resolve the problem please reply and I'll do what I can.

Originally posted by @DieDaily in TheGrimsey/StoneholmForge#14 (comment)

Same issue for me: no villagers to see when using the mod on a dedicated server.