As a test run I gave out tracking number's this time around to customer's I have built a history with and know by now they are not an OPSEC issue, besides one new comer by mistake from working to fast and not double checking.
Tracking number's can update at a variety of time's. When it is collected from the collection box, when it is processed that night, it might hit the next center and then show past update's, or it might not update until it hits your local post offices. When it is collected from the collection box, when it is processed that night, it might hit the next center and show all the past scans, or it might just pop up in your mailbox and show "Delivered" a day later.
So besides the usual variable's in the USPS collection process there's also an extra day's worth (which should not be a lot at all I would think) of mail. This was a good test run but from now on it's just going to be check your ID, besides some exceptions.
Edit: 2:55am all of the order's have been Accepted and are displaying their Estimated Delivery Date, besides 1 that was sent using Express Priority shipping.
So they could be sorting Express mail separately and it will update later tonight or maybe they are making up for lost time and just loading Express package's up to get them to their destinations and they'll get scanned in their next Distribution Hub, or one other possible reasons listed above.