[0.17.14] Spawners displayed on map creation preview but not present in game

[danielkwinsor]

Seed 2984323196
Set to Deathworld Marathon, and if relevant also settings like railworld.
View small cluster of spawners or worms to the south-southeast of the center starting lake.
Enter map.
View small cluster does not exist.

Screenshots available if necessary, but it's kind of a lower priority bug, imo.

[Klonan]

The preview isn't and won't ever be perfect, and doesn't take into account all the factors