Diplomacy UI Stuck With Unavailable Item

Say you're in the diplomacy menu preparing a trade, and you select an artifact. If you don't complete the trade, that selection stays selected if you leave the menu and come back, no issue there.

However, if you use the item, (i.e. put it on a ship) it's no longer visible in the UI, because it's no longer available for trade. But because it was selected before, it still exists in the trade offer, and now you can't propose a trade because you're offering an item that you don't have available. And because it's no longer in the UI, you also can't deselect it.