Use the following instructions at the buttom, Support tool:
https://esupport.stardock.com/index.php?/default_import/Knowledgebase/Article/View/496/161/general-galactic-civilizations-iii-troubleshooting
Use the tool to generate a debug log when it happens. Submit said debug report to Stardock along with your last autosave prior to the bug + debug.err + prefs.ini.
Maybe they'll be able to trigger something, we never know.