Commerce Manager: Unable to save/update shipment address in purchase order

Description

Steps to reproduce

1. Open Commerce Manager.
2. Create a new purchase order and choose a Billing address from the dropdown box.
3. Choose the same address option for Shipping Address,
4. Edit the Billing address fields "Line 1" and "Line 2".
5. Open the billing address and see that it is correctly saved.
6. Open the shipping address and see that it is same as billing address but should be the one saved in step 5.
7. Select the proper address from the selection and click OK.
8. Open the shipment address again > it reverted to the billing address.