I've been having that very problem playing as Rome on Alex exe.
If I am sieging a city and I'm attacked by a reinforcement army and end up capturing the city I get a CDT when I choose one of the settlement options.
This was a autosave problem with vanilla but I have autosave set to False in my preferences so I know that's not what's causing the crash.
I have deleted the background script in my play as Rome folder and that has stopped the CDT's, I tested it yesterday on three different sieges and no crash also there is still some script entries in Rome Shell after each end turn so slightly confused as to what script is running.
Anyway having deleted the background script am I going to miss out on the Roman Civil War? or is this going to cause me more problems later on?
And is there another work around without me having to delete the script?
Sorry for all the questions