The bug is known, but if you still have that save, please upload it so I have more potentially needed material to study. I will hopefully get to it soon, only crashes have a higher priority at the moment.
That said, culture of collapsed civilisations remaining present is a feature of the mod and intentional and (likely) unrelated to the issue.
That said, culture of collapsed civilisations remaining present is a feature of the mod and intentional and (likely) unrelated to the issue.