This is broken too: Threadless shopping cart logins

Threadless is my favorite place to buy t-shirts, period (this includes any offline stores). I've bought dozens and dozens of them and I even subscribed to the shirt of the month club for a year, but every time I make the mistake of throwing a few shirts in my virtual cart and then remembering to login afterwards, I lose all my previous selections. I buy shirts there every couple months and in between each visit I often forget about this bug in the long lost hopes someone fixes it. When I got hit with it for the millionth time tonight, I took a few quick screen captures to demonstrate the problem.

Here is video of the shopping cart failure

The first 30 second bit is me adding a shirt to my cart, continuing to shop, then logging in and trying to check out, but my cart turns up empty. Not good.

The second shorter bit is after I add a shirt to my cart, go to check out, then remember I should login to grab my saved address/credit card/etc info, but as you can see it clears out the cart. Oftentimes I lose 15 minutes of shopping time picking out just the right shirts in my size because the cart clears out every time upon login. Then I have to try and remember all the designs I liked and put them back in the cart (often I just quit and shop the next time they send me a 'new releases' email)

Threadless, I love you guys to death but I've encountered this bug for about two years and would love love love it if you fixed it with some cookie/session storage of shirt selections so I don't lose my cart upon login

(why login? if you don't login, it basically creates a new threadless account with your exact same details and there was a time I was subscribed to their mailing list three times under different "accounts").

update: by the power of greyskull, this has been fixed!