I think to found a bug and potential fix about it
In the method settings_onSave() of the app/admin/controllers/Locations.php class there is
$this->asExtension('FormController')->edit_onSave('edit', params('default_location_id'));
I don’t understand why there is a default restaurant id.
I think that the correct way is to pass to the method the current restaurant id, then I suggest that
$this->asExtension('FormController')->edit_onSave('edit', $this->getLocationId());