Ebay Drop ship?

I ordered some padded shipping envelopes from an ebay seller and the first tracking entry showed within my state and now it shows having traveled to multiple states thru “Amazon shipping partner”. Can anyone decipher what is going on? Is this a MFC drop ship gone bad using Amazon?

It looks like FedEx Ground Economy or Pitney Bowes shipping where the last mile is handled by USPS.

Wondering if this is a twist in a seller using Amazon MCF ???

With that said, the route through IL to MO is very similar to what we have seen with Ptiney Bowes shipping which is delivered by USPS in the end.