I had the same happening when the settlement was of a faction (descr_regions.txt) not present in descr_strat.
For example:
If I add this province:
Britannia_Inferior
Eburacum
britons
Brigantes
232 41 198
lead, dogs, pigs
5
5
But if the britons are not present in descr_strat then the game will CTD when scrolling over the settlement.
Edit: you said it CTDs when scrolling over a random settlement... now that is odd...
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