With the most recent patch today, it seems that there’s been a small bug introduced with the trading menu. Before this patch, whenever you listed an item for sale and listed all of them in your inventory, the item’s listing menu would close. However, it now will remain open and claim you have a quantity of 1. If you try selling, it just says you have none to sell.
This bug isn’t gameplay affecting or stops you from doing anything, but it is rather annoying, especially when listing multiple items.