The parties have retained all of their troops. There doesn't seem to be any attrition at all; they're all just frozen in time. Of the 6 mods I have installed right now, Diplomacy is the only one that is meant to change anything campaign-wise, as the rest are UIExtenderEx, Detailed Character Creation, and the associated libraries.
I have also found another reproducible error: once I am within the range of the battle, moving my cursor causes the crash. I'll keep experimenting.