Cant buy more biscuits when clicking on them in your invetory

Just played a game as Poppy that does not have health potions in her recommended build. So i would go to the shop type in "health" and buy a potion, and because of my masteries, they turned to biscuits. When I am in shop I would click the biscuits in my inventory and what would show up in shop are potions, and the option to buy the potions were not available. This made me type in "health" and I would have to buy potions( which turned to biscuits in my inventory) that way. That unfortunately does take some time and isn't as efficient if someone is pushing your lane