Arretium CTD

Besieging Arretium with my Casse Bren (who is awesome, btw), I'm attacked by a supporting Romani army.
Twice I have played the battle, winning both of them, but the game crashes when loading up the campaign map window.
The second time I made sure I annihilated every last man of the city garrison (the reinforcement army in the battle) to see if that solves things. Didn't help. To get around this CTD I just auto-calced with the auto win cheat.
This is around 208 BC btw, the Romani are only just churning out those Polybian units if that's relevant.

A leftover of the reinforcement bug, maybe?

Seems like it.
Was there any enemy family members (from any army) that got away?

The first time, yes. Second time, no...I think.

I'll do a couple of tests with the savegame I still have: eliminate all family members, and if that doesn't work, eliminate both entire armies.