The fix you need is hidden deep within the NCF topic.
It changes the creature spawn rate for dummy creatures from 0 to 1.
But I can't guarantee it will help. I have one concern: in Heroes 5, the newer the file, the higher its priority. With a simple NCF, everything is normal – ncf-core is created first, followed by mods for units and the megapak, but this fix, which changes the spawn rate for all dummy creatures, was released relatively recently. Does that mean it will have a higher priority than all the mods released before it? Or did the author take this into account? It's unclear.
Added 6 minutes later
It worked, thank you very much! 😎