MarketPress broken after upgrade

Hello, i'm a paid monthly subscriber and recently upgraded my site to the latest version of MarketPress.

Before the upgrade my site had the "Choose Option" button on my variable product listings, this worked fine, my customers would be directed to the product page where they could select the correct variation.

Now they are directed straight to the checkout page without being able to select the correct product variation.

How can i get back the original functionality????

Kind regards

Jason