We are trying to understand why importing contacts from CSV files with Address, City, State, Zip but no Country results in addresses with countries like Uruguay (for some CA residents), Yemen (for some South Dakota residents), and today, for the first time, for a bunch of CA residents, they were assigned "Guinea-Bissau". Although we have different staff doing different imports, the majority (e.g. ~3000 out of ~3060) of our imports DO end up with Country="United States"
In "Adminster > Localization > Languages, Currency, Locations" we have Default Country set to "United States". That was set when we first configured Civi long ago.
Is there some other setting that deals with setting the default country on import? Should we solve this by always adding a Home-Country column to CSV imports? That seems cumbersome, but will do if that's the only solution.
BTW, we're running WP 4.8.2 and CiviCRM 4.7.22.