For a shopping cart/product configuration to go through the approval process correctly, you need to have approval values available from the Status field.
To add values to the Status picklist
- From Setup, go to Create > Objects and click Product Configuration.
- From Custom Fields & Relationships, click Status.
- From Picklist Values, click New and add Approval Required and Pending Approval.
- Click Save.
These values will now be available from the Status picklist for a Product Configuration object record, which also means the status can appear in the Status field at the top left of the Shopping Cart.