That's odd. It definitely said "out of stock" earlier. Now it is showing as available. The soft cover was also showing as limited stock.
It could be something to do with how the system counts stock available to order based on whether there are some in baskets but not yet completed, effectively reserved for a period of time, which then are released back for sale if not purchased after a certain time.
Pure speculation in my part, but either way I guess if anyone wants this they should buy it now or risk waiting for a second printing.