Sorry I missed this. Yes, even when it says a package is on the truck it may just be relaying logistical information (where the package is supposed to be) and may not be accurate until there is a another physical scan on the package and the tracking information is updated - then you get an email with the update.
A lot of shippers are struggling to keep up with demand. Amazon is a month out from what I hear. Order forms and shipping labels are created and go into a bin to be picked by warehouse employees, boxed, then finally given to a shipper (UPS, FedEx).
UPS and FedEx are not experiencing any delays afaik. Volume is down because business to business is the bulk of their revenue.