The second picture is the key here. There is a problem with the system.
When an item does not have options, it will say "In Stock" or "Out of Stock" at the top, just above where it says the item qualifies for free shipping. This works as it should.
When an item has a drop-down list, it always says "In Stock". Then, when you click on the drop-down, you discover no options, meaning it really is not in stock. When all items are out of stock, it should change the status at the top of the page as well.
It's a little confusing and makes people think something is in stock when it is not.