[mrsanborn]

A couple of things could have happened all of which if the parcel was properly addressed by the sender, are employee error. First, the parcel could have been sorted to the wrong carrier who endorsed the parcel as undeliverable or it went to the right carrier and was endorsed undeliverable.
Before the parcel is retuned though, a clerk usually verifies with a scheme board or knowledge that the parcel or letter is in fact undeliverable. With the downsizing of the clerk staff or managements refusal to supply the resources to this position or the clerks lack of knowledge of the delivery scheme causes the person working this position to take the carriers endorsement at face value. My guess is that with the explosion of deliveries here in The Villages, the clerk staffing is boosted by the hiring of casual employees who are usually not given proper training. Also, your carrier is a contract carrier and not a direct USPS employee. Been there.