Shipping cost is not updated after adding new shipment.

Prereq.: Pending order exists with with shipment and payment selected.

Steps:

1. Add new shipment to the order with different cost using REST API.
2. Go to Commerce / Orders / <order_id>.
3. Switch to Items tab.
4. Check Shipping cost.
5. Switch back to Summary tab.
6. Click "Go to details" in Shipment section

Actual result: Last Shipment is displayed, with different cost than the one in point 4.
Expected result: Shipment created when creating order is displayed, matching cost observed in point 4.