function wpf_user_register_start( $user_id, $post_data ) {

    if ( isset( $_POST['payload'] ) ) {

        wp_fusion()->settings->options = get_blog_option( $_POST['payload']['site'], 'wpf_options' );

    }

}

add_action( 'wpf_user_register_start', 'wpf_user_register_start', 10, 2 );