Kundane in the original Baldur's Gate 2 had an undocumented bonus of one extra attack per round. Was it an omission or design decision to not have this attacks per round bonus carry over to the new Cutthroat +5 item?

Thanks for the reminder! I will add the attack per round bonus to the upgraded item (and will also increase the upgrade's price to compensate the sword's new ability )

Surely Kudane was powerful enough already!