This is a kind of tracking notification from USPS. You usually get this message “in transit to the next facility” notification when your package or mail leaves one facility of the USPS to another towards the recipient.
Most of the time USPS will deliver your mails on time but some people have recorded complaints with mails failing to reach destination on time.
When you call USPS to follow up they sometimes have no clue where where your parcel could be, while unwittingly the item could have reached another distribution center, then transferred to your local post office without getting it scanned in to the system. Such errors occur but eventually the mail manages to reach the owner.
When you post your mail in your Local Post office, delivery of the item commences immediately and so does the tracking and notifications. Usually a package goes from your local post office to a central area facility for processing and sorting. After processing and scanning the mail is scheduled for the next facility and that is when Usps sends ‘In transit to next facility’ tracking message is sent. But because things don’t always work as they ought to or because some clerk somewhere is lazy to scan, the mail moves on without trace and arrives in your mailbox without little communication.