It appears to be a beneficial bug, because the shooter does apologize when the explosion is too close to the party, but I have used carnage bows quite extensively without noticing any actual disadvantages. (I equip the whole party with carnage bows and shoot arrows at monsters across the room who are barely visible between the monsters up close. The arrows hit one of the close monsters instead and blow up, damaging all of the monsters in close without appearing to actually hurt my party, despite the shooter's apologies.)3DO appears to have fixed this glitch for MM7 and MM8, so I tend to avoid bows of carnage in those games.
