Same here… the error log of this bug:
id was called incorrectly. Product properties should not be accessed directly. Backtrace: do_action(‘wp_ajax_wfg_add_gifts’), WP_Hook->do_action, WP_Hook->apply_filters, call_user_func_array, WFG_Frontend->wfg_ajax_add_free_gifts, WFG_Product_Helper::add_free_product_to_cart, WC_Abstract_Legacy_Product->__get, wc_doing_it_wrong. This message was added in version 3.0.
