Error in table state_province for Wales
I think you're right - good catch. See https://github.com/civicrm/civicrm-core/pull/19802
FYI in my database there isn't a restriction for uniqueness for the abbreviation field - the unique constraint is defined here: https://github.com/civicrm/civicrm-core/blob/da28128b812d4ae53c52abd8073656c61bbc4cc7/xml/schema/Core/StateProvince.xml#L70-L74 and it's name and country_id.