WooCommerce Edit Product (admin) and Select Menus

I noticed today that there seems to be an issue with the Select menus and WooCommerce in the edit product page. I created a couple of post object fields for the product post type. I also set them to be allowed to be null. However when I try to click on the ‘x’ in the menu to deselect the item (previously saved) the ‘x’is grayed out and cannot be clicked. Whenever I do click the menu just opens.

This does not happened for any other post types, just WooCommerce products.

Any ideas?

Cheers!