We are checking the product link provided and see that the adding to cart is working correctly. Please explain the problem in more details. What steps should we take to reproduce the problem?
Our theme and this function operate with the default Woocommerce actions. The plugins modify these actions that is why your function does not work properly. Please contact the plugin support.
Our theme is compatible with a lot of WooCommerce plugin. But specifically in this situation, the AJAX function is not working with custom fields added by other plugins. So you just need to disable this option in Theme Settings -> Product page. It means that this plugin is not compatible with all themes that use custom AJAX add to cart function. We are not able to fix this globally for all similar plugins.