Could simply be USPS which caused the delay. A lot of places are having a hard time keeping up with the mail due to Covid. I can speak for my own local situation, and have heard of other areas having the same problem. For me, ~60K population in this county. Sent a BD card to someone 6 miles away. Took 9 days to get. I could have walked it there faster! Also, the receiver of the card, and others in her small town, are getting week long delays in their mail. They know what they should receive for the day (emailed daily digest) but it takes up to a week to actually have it put in their mailbox. Per the local newspaper they are very short staffed and having problems hiring. I'm thinking this situation can happen anywhere across the US.
From the mouth of USPS directly:
USPS products and packages
may require more time to be delivered due to limited transportation availability as a result of the ongoing COVID-19 impacts.