Tried the same mission twice from a savegame from a few minutes before the crash. This time no crashes so I haven't been able to reproduce.
I was looking downwards from the hill to the north of the town. Had the town that is getting pounded by mortar shells in my field of vision. Since it was a PhysX crash, I wonder if some of the mortar shell effects down below could be related ?
Now that the usual dump files do not contain anything helpful, perhaps it could be possible for the physx code to write debug info to another file which could be sent to you in case of physx crashes.