Not a major bug, but this happens everytime I try and buy magic scrolls through an NPC Mage. After I have 9 separate scrolls to purchase, the 10th one automatically adds an extra scroll to my purchase. For example, if I have one of each separate magic scrolls and I add a 10th scroll, it bumps up my buying quantity to 2. Even though I double clicked one once. After I reach 19 scrolls, on the 20th, it will add 5 to the cart!