Yeah, tracking iPhone shipments now requires expectation management and patience. I ordered my phone a week after the preorder date so this clearly isn't being handled as an expedited shipment. They will get it on the plane when it's least expensive for them to do so.
My iPhone 7+ AT&T 128GB black went to Shipped status on 10/3. UPS originally estimated delivery today, 10/6. But early this week the tracking data started jumping back and forth between China and Korea, then the estimated delivery date went to "information unavailable". Now this morning I'm finally showing a departure scan from Korea so we'll see what happens. From what I'm reading here, this is pretty common.
All along Apple's order status says "Delivers 10/12-10/18" so despite the confusing info from UPS and the initial 10/6 delivery date estimate, which was just a tease, I believe Apple will make their quoted date range.
I'm just going to watch the progress an not assume a delivery date is real until the package has landed in the US.