On PrestaShop 9.1.3 the State / province dropdown can remain on A Coruña when creating or editing an address. Checkout and back office both look “saved”. The selected province is wrong. There is often no validation error.
This is a state/country id mismatch in the address form (locale, default zone, or a JS/select that does not refresh when the country changes). It is not the customer failing to click.
What to do
Reproduce in FO and BO with a second country/province. Inspect the selected id_state versus the country. Fix the form refresh and the default state list for Spain. Retest guest checkout and logged-in address book. Do not “fix” it by deleting A Coruña from the zone table.