'Blank' address after civicrm_location_update

eg Suppose I have a location with just a phone number and no address. I update the location through civicrm_contact_add but afterwards there is an address shown when viewing the contact. It just has the state and country when previously they were not shown. If I then update the contact through the web interface, the state and country disappear.

This happens even when doing a simple update without actually specifying anything really to update, eg

$params = (
[contact_id] => 123,
[is_primary] => 0,
[location_type_id] => 2
);

civicrm_location_update($params);