It's nwn feature. There may or may not be something that could provide a change or a fix but if there isn't something in level of nwnx, not something we can fix without some custom adjustment, and because it happens in engine levels it can be unpredictable in situations we can't foresee.
"Free attacks applied to users of creature weapons are implemented as additional attacks applied at end of the attack progression and continue the same BAB progression rate as the class dictates (-3 for monk, -5 for all other classes), ignoring the normal "full base attack" effect. "
"Free attacks applied to users of creature weapons are implemented as additional attacks applied at end of the attack progression and continue the same BAB progression rate as the class dictates (-3 for monk, -5 for all other classes), ignoring the normal "full base attack" effect. "