Double Lavianga's spirits mana flask not working

If I equip Waistgate Heavy Belt unique it allows me to equip mana flask in either slot. When I equip Lavianga's Spirits Gargantuan Mana Flask in both Life and Mana slots only one effect is given the other flask does not add additional effect - extra regeneration. It does not say anywhere that only one flask effect is given as a unique modifier. This either needs be fixed or reworded, reworked.