Its linked to Chaos uprising inky events. It only chooses from low loyalty/security towns though.

Got it, but any available info on those numbers?

40 loyalty is already considered not low by the vanilla town mechanics, since Prosperity rises from that point onward. Perhaps the treshold for Chaos Corruption should be lower?

I honestly felt that this was too "random" and unforgiving - the town has no tells whatsoever of being corrupted by Chaos. In fact, its improving everyday (I'm actively protecting villages, resolving issues and managing the town)

I've asked about the specifics, will get back to you later

So i've had an answer about how it works, the strongest faction of either bretonnian or empire culture, if they have more then 1 town, the event will then happen in the town with the lowest loyalty of said strongest culture faction.

So my initial reply was also wrong, even if you have 5 towns of loyalty 100-99-98-97-96 and you are the strongest faction with empire or bretonnian culture, you will lose the 96 loyalty town to chaos corruption.

This mechanic was meant to stop AI factions from snowballing but yes it also affects player kingdoms.

The whole mechanic will likely be revisited in the future when chaos becomes playable or other changes

I see, well I guess I was in fact aligned with Reikland and we were dominating the whole map

Anyway, thanks for taking your time to check this

Happy new year