Oh shit, hahahaha. Shopify changed their process. It used to be, once you added something in your cart, it is yours, no one else can buy it out from under you. It worked pretty well at preventing checkout errors. But obviously caused some issues with users not checking out and leaving items in their carts, this forces LRG runs to last longer than it would naturally. This is why you could sit there on the site for an hour or something and still have a chance for it to come back in stock. An item is "sold out" when all copies are "held" in carts or purchased.
NOW, the process is first to complete checkout gets the item. This causes checkout errors where you'll get a message that says the order could not be completed due to lack of stock. But it also causes products to sell out naturally, an item is only sold out once all copies have been sold.
Apparently a lot of folks are pissed that they were in the checkout process of Darius CE and were getting checkout errors due to lack of stock.