The Ghost Ward (utility 12) has some weird interactions with the shop.
1. All of your items slots say 10 in the bottom right corner other than your biscuit until you buy something.
2. It moves another item into the slot where it should be in the shop.
3. If a consumable is put into that slot in the shop (where your ghost ward is currently), the shop lists you as having that consumable even if you use it. If you buy more of that consumable, it shows you having as many as you had + new ones.
4. If you have all 6 slots full (which only shows as 5 slots full in the shop), you can go to a new item and have the buy button highlighted. The button is clickable, but nothing happens.
5. With the items disorganizing your inventory, it will show that you are trying to sell the item that you clicked on, but you will sell the item that is currently in that slot instead.

How to reproduce:
1. Start a game with the Explorer mastery.
2. Buy items (including consumables).
3. Either sell things or fill up your item slots to reproduce the appropriate bug.