Without both these mods, spawn looks like:

With these two mods, spawn looks like;

Removing Flonters or industrial revolution does generate decoration.
This also seems to impact ore gen by other mods that are not astromine.

the current worldgen in flonters is a temporary measure until this gets pulled, does it only happen when both mods are present or when either of them is?

It only happens when both mods are present.

Here's the server log, in case it helps:
latest.log

I have done some more testing. Only removing Flonters from my pack doesn't solve the entire issue. Though overworld biomedecoration works again, no ores besides astromine's are generated.

Removing industrial revolution and flonters from my pack does make all ores generate again. I've picked this up with the indrev dev.

This got fixed on Industrial Revolution's end. Thanks!