I've been trying to replicate this bug but it doesn't seem to have a pattern.
Some areas of my map are capable of spawning pragmium nodes, where as other areas only spawn the mobs (beetles, lizards, scorpions).
I can eliminate some factors based on tests:
It is not affected by the size of the zone.
It is not affected by the recency of the zone.
It is not affected by the texture the zone is placed on.
ScreenshotsIn this particular instance, I used volcano texture to show contrast.
I'm including my .map file for those wishing to investigate.Check either Volcano. No pragmium is spawning. Then check the central boss pit. Pragmium is spawning. Check the southeast boss pit. No pragmium. Then check either quarry. Pragmium. Northeast alien island.. Pragmium.