Product added to cart without choosing variation

There is a little bug with e-mail pop-up on product page.

When a e-mail pop-up is activated on the product page and redirection to checkout page, and the customer dont choose any variation, the product is added to cart without variation.

Usually woocommerce gives you alert that you neeed to choose a variation first before adding product to cart, but with e-mail pop-up it bypasses it.

Hope you can fix it asap.