Product version order doesn't save

As I add product versions, they seem to reorder themselves. At first I thought it was cheapest on top, but then one I made didn't do that. Also, if I reorder manually, it does not save. I get no indication it is saving (unlike anything else I do when making a product) and I don't see a button where I can save. Even if I hit save on the product version itself, it doesn't keep its order.