Bug w/Hack

Seems like hack should trigger charge-set, but it doesn't seem to: <1027hp 405m 1049mv 27100tnl (-23.18%)> warc Ceyraia appears more confident as she shouts 'Mourn not the strength of death. Sown to Reap. Cull the Weeds!' Urgok steps out of the shadows. Urgok hacks at your arm with all his might! You hear a crack as Urgok's weapon connects with your arm! With your shattered arm, you can no longer hold onto a silver-bladed poleaxe. Urgok's mighty swing DISMEMBERS you! You feel much too macho to scream about being attacked like some kind of sissy. An orcish guard is gushing blood. We were not already fighting, and chargset didn't even fail. Bug or by design? Thanks!