Currently the ShipNotify and List Shipments API requests only return the master tracking number for an order. We need it to return all tracking numbers for an order.
2 years later and still not fixed. I can't reconcile my Purolator invoices with Shipstation because half the tracking numbers are missing from the shipping manifest and api queries. Seriously, Shipstation developers, please fix this issue. It's not right to give your customers an incomplete product.