I think it's just the Canadian online store- items that sold out weeks or even months ago (Powerhouse Crop, for example) will randomly flood the WMTM section! When you click, it even looks like you can add to bag, but then it doesn't show up in your cart and when you go back to the item, only then does it say "Out of Stock". Looks like they've fixed this round of haunting for now, but it's so annoying as I just get my hopes up!
The US side used to do that all the time, but I think since they took WMTM down for a while to fix it, things have been better. That used to drive me crazy though, I'd think an item was available and then you clicked on it and nothing...