Bug 378,992,956: Currency in stash tabs sometimes does not show up for sale in Currency Exchange

This especially seems to happen with fossils and scarabs.

Steps to reproduce:
- Sell something in the currency exchange
- Try to sell a different thing in the currency exchange, which you know you have
- Sometimes, Faustus will say you don't have any of this item to sell, even though you definitely do. The issue will resolve itself after several minutes or if you go to your stash and pull the item out into your inventory.