Just a quick update. I found out that Planetary Diversity uses their own variants of Machine and Hive worlds. I'm using that mod too, so that's likely where the issue is coming from. Will try without Planetary Diversity and see if this still happens!

Should be fixed now (version "1.6.0")!?

I have removed the Planetary Diversity Mods and tried again.

Unfortunately, it is still doing it. As soon as a world is terraformed to a Hive World, all of the Pinnacle Society Districts disappear.

Hm the type of Pinnacle Society Districts changes too on terraforming, should be automatically transform after some time!?

They don't. You can see the Pinnacle Society District "categories," but the count for each one is always 0. If you build or destroy another district you can sometimes see the Pinnacle Society ones pop in for a split second before they disappear again.

Also, Confirmed that if you terraform Ringworld Segments to Hive/Machine worlds, those Pinnacle Society Districts work just fine.

I noticed that the Pinnacle Society districts also do not appear for non-standard Arcologies (like Eco-Arcologies) for the Planetary Diversity submod More Arcologies.

Can you both try the new beta version from
https://steamcommunity.com/sharedfiles/filedetails/?id=2811428998

I tried the BETA Mod and there was no change. The Pinnacle Society districts are available on "normal" planets, but as soon as you terraform them to a Hive World or Machine World, they disappear (have district counts of 0).

I am not using any Planetary Diversity Mods.

OK updated the beta again (no time to test yet).

That did it! Thanks so much!