The "Add to Wishlist" button may work improperly in a product type "Grouped product" because the hooks "<strong>woocommerce_before_add_to_cart_button</strong>, <strong>woocommerce_after_add_to_cart_button</strong>" are missing.<br />Please, ask your theme developers to check the theme templates or <a href="https://templateinvaders.com/help/" target="_blank">contact us</a> for assistance.