API update order with promotions

i have multi vendor 4.15.2, clean without any added addons.

At changing an existing order via the rest API like quantity amount, the promotions are not updated.

I have a promotion set up when buying more than 3, it works fine on the website directly, it also works fine when creating an order using the API, but not when updating an existing order.
For example, if I create an order with a quantity of 2 and update it to 4 - the discount is not given, and vice versa, if the customer purchased 4 and received the discount and then I update the quantity with the API to 2 - the discount remains




It is not only the API that does not reapply the promotions to the existing orders, but also the admin panel which works exactly the same way.

You can change this behaviour by changing the value of the tweak do_not_apply_promotions_on_order_update in config.local.php from true to false. However, let me warn you that this is not recommended and may cause unpredictable behaviour as this functionality is outdated and hasn’t been tested in literally years.