This is happening more and more.
My store has "Enable city and region lookup by postal code" enabled.
My customer enters their address at checkout. Then some address correction system substitutes a nearby but WRONG city.
The following substitutions have happened:
Providence, RI was changed to PAWTUCKET (caused a lost package)
Bangalore, KA, India was changed to CARMELRAM (Customer caught the change and notified me)
La Jolla, CA, USA was changed to SAN DIEGO
Canoga Park, CA, USA was changed to LOS ANGELES
Rancho Palos Verdes changed to LOS ANGELES
Often, these substituted US addresses are not recognized by the USPS postal address lookup.