I believe the freeze is related to either Casta’s enemy AI researching modded technologies or interactions with jammer radars.

The freeze happens at the exact same game time every time.

I tested disabling only normal radars (since jammer radars are needed to even play Casta), disabling radar scanning, and manually removing visible radars — the freeze still happened.

However, when using a command to delete all radars, including jammer radars, the freezing stopped.

Fully removing the Casta mod also fixes the problem permanently.

This happened hours after finishing Casta and moving to a different planet, which made it pretty frustrating — if it had happened early on, I would have just removed the mod straight away.

Right now, the only fix I can think of is disabling Casta’s enemy AI entirely, removing all jammer radars and modding myself in another way to get battlefield data — but that kind of removes the whole point of the mod.

Just experienced the same freeze, after using the trial and error method I figured out that is was Castra causing it sadly

zuluko figured it out, remove all your artillery, the freeze happens when all the enemy bases are destroyed without them being able to build another.

I just wasted multiple hours on this. Disabled /enabled mods 1 by 1 and eventually found out that Castra was the culprit. Thanks to Jimbob's comment, I was able to rescue my 1400h save file from being totally bricked.

The issue can be found in on_tick_update_data_collectors, in this loop:

        while not collector or not collector.valid do
            collector = storage.castra.dataCollectors[math.random(1, #storage.castra.dataCollectors)]
        end

If the list of collectors is not empty, but all collectors are not valid this will keep trying forever.