I’ve seen a pattern with things I've shipped via Priority mail. If i take it to the human behind the counter, pay my postage, AND they scan the label in my presence, i have no issue with it getting delivered and tracking will show a pretty direct route to the destination.
If i use the self service postage machine and the drop box or pay online and leave it for my postman, i don't see a first scan for days. Also the package tracking number will show it crossing the country or some crazy route to go 200 miles. Or it will show it sitting in some city 1000 miles away for days but gets delivered a couple hours later then tracking updates to delivered.
Now, I only mail things at the counter and witness its first scan when I pay the postage.