(let's see how convoluted I can make the subject and the explanation!)
I buy items from auctions. Gems. Because people are selling them, and I have too many currants, and I give them to giants and gain XP and well, isn't that fun?
So on this weekend's run, it's not working right. The gems that I acquire via auctions (and not my own hand) don't properly appear in my inventory at donation time. For example, it might show that I have zero moonstones (though the moonstone still shows, with a count of 0), although I just bought four at auction. I can donate them one at a time, still showing a zero count, but can't donate them as a hunk. And when they're actually gone, there's no moonstone showing in the donate screen.
This works for all gems! Or rather, is broken in the same way for all gems!