When your customer orders Printbest products and non-Printbest products together from your Etsy store, we fulfill only the Printbest product order, and then ship it out. Often, we ship it out faster than the other supplier.
Etsy is unable to show partial shipment, so when the first product is shipped out, the order status automatically changes to “Shipped” (even if the second product hasn’t shipped out yet)
Because of this, Etsy is also unable to show different shipping details for the same order. This is why you only see the tracking number and shipping details for one of the packages.
Since this is a limitation of Etsy itself, it is unfortunately not something we can fix on our end.