Hi, i just found another bug.
I was besieging the bloodkeep (owned by Sylvania) during the campaign while playing Stirland.
I passed 2 of the three wall lines. When the game crashed, i had several archers/crossbows shooting and a mortar unit too. I had a few melee units engaged in combat (about 3 units max).
I got an empty error message, with no phrase in it.
You have the m2tw log attached, with my dxdiag file.