ModMash Splinter, Underground + Subways (1.1.42) ...

Error while running event modmashsplinterunderground::on_chunk_generated (ID 12)
...splinterunderground__/prototypes/scripts/underground.lua:474: bad argument #2 of 2 to 'random' (interval is empty)
stack traceback:
[C]: in function 'random'
...splinterunderground__/prototypes/scripts/underground.lua:474: in function 'generate_surface_area'
...splinterunderground__/prototypes/scripts/underground.lua:656: in function <...splinterunderground__/prototypes/scripts/underground.lua:630>