Unifaun Fix for CDON (Sharespine)

functions.php

<?php
/**
  * @snippet       WooCommerce - Unifaun plugin by Redlight Media - Add default shipping method to orders missing shipping
  * @author        Redlight Media AB / Christopher Hedqvist
  * @compatible    WooCommerce 4.2.0
  */
add_filter( 'ac_wc_unifaun_order_list_shipping_method_id', 'redlight_unifaun_order_list_method_id', 10, 2);
add_filter( 'ac_wc_unifaun_post_shipment_shipping_method_id', 'redlight_unifaun_order_list_method_id', 10, 2);
add_filter( 'ac_wc_unifaun_post_return_shipment_shipping_method_id', 'redlight_unifaun_order_list_method_id', 10, 2);
function redlight_unifaun_order_list_method_id( $method_id , $order ) {
    // For all orders created via rest-api, set flat_rate with instance 10
    if( 'rest-api' === $order->get_created_via()){
       $method_id = 'flate_rate:10';
    }
    return $method_id;
}

add_filter( 'ac_wc_unifaun_order_list_shipping_instance_id', 'redlight_unifaun_order_list_instance_id', 10, 2);
add_filter( 'ac_wc_unifaun_post_shipment_shipping_instance_id', 'redlight_unifaun_order_list_instance_id', 10, 2);
add_filter( 'ac_wc_unifaun_post_return_shipment_shipping_instance_id', 'redlight_unifaun_order_list_instance_id', 10, 2);
function redlight_unifaun_order_list_instance_id( $instance_id, $order ) {
    // For all orders created via rest-api, set instance id 10
    if( 'rest-api' === $order->get_created_via()){
        $instance_id = 10;
    }
    return $instance_id;
}