Henchman Bug

The Henchmen Bug is a known misfeature of the NwN game system in which henchmen become inappropriately hostile after wandering into a harmless magical effect - regardless of whether they are actually susceptible to it or not. As in Avlis, this bug usually crops up with magicians using their familiars in combat.

Typically two situations cause this bug: 1] a familiar charging as as a caster throws an area attack spell (Fear, Fireball), or 2] a familiar wanders into a static area of effect (Darkness). In all cases, being immune to the spell (does not affect the inappropriate effect, so casting ultravision on a mage's familiar will not prevent them from becoming hostile if they wander into a Darkness that mage casts. Worse, the henchman still retains its hostility to opponents, so often nothing appears to be wrong right up until the familiar sneak-attacks their own magician.

There is no known way to prevent the henchmen bug from occurring. Only quick unsummoning can make the problem go away.