When 6 Runes of the Centaur are equipped and you pick up your Healing Turret while moving the full cooldown of the Healing Turret (20 seconds) is activated rather than reducing the cooldown by 5 seconds, which is what should happen when you pick it up.
This happens whether or not you immediately pick up your Healing Turret, as long as you are moving and have 6 Runes of the Centaur equipped.