selling items as stack bug (poe2)

When you try to sell currency as a full stack, the npc vendor gives you gold coins worth of a only one unit. For example: if you sell full stack (30 units) of Orbs of Augment, vendor gives you 30 gold coins for the stack and if you sell thouse same 30 Orbs of Augment one at the time to the same vendor, you get 30 gold coins for each totaling 900 gold coins.