Orders are getting duplicated with Custom Post-In integration. After posting a new order then try to update the same order they are getting duplicated instead of just updating the same order with the same ID. For example updating order status by setting OrderStatus to "shipped", "unshipped", "paid", "cancelled" does not do anything just creates a new order in ShipRush.

According to documentation it says you just need to post the order to shipRush again in order to update it as long as the order have the same External or Order ID. I am currently in sandbox.my.shiprush.com doing the testing.

Is there something i am missing here? whats the best way to update the orders and avoid duplicates in shipRush.