This is likely related to another minor issue that I've encountered, though I can't be sure.
I'm sure many people have noticed that sometimes if you have multiple full bags of rye grains, or barley grains (or full boxes/baskets of other things), they will not always stack. And they should, because they are not decomposing, so they should be an "identical" item.
Well, some testing revealed it's because the ownership of the underlying bags/baskets is not always set correctly. The way you can tell is that if you attempt to [D]iscard the items, some of them it will not let you, saying that items that you don't own can't be discarded, while others it will allow you to [D]iscard.