1) There's a very obvious bug:
The "flails" weapons length is "3" for the first, "6" for the second attack.
2) You need the heros1_6 mod to look at the battle as well.
It's late (early, in fact
) .. won't go hunting for it now ...
Without knowing if bless, swarming etc was involved it's very hard to tell if there's something wrong from the combat log excerpt alone ...