Amending relationship types has broken civi case
Check the name_a_b and/or name_b_a fields in the database table civicrm_relationship_type. Check that they match the &lt;name&gt; entries in the &lt;CaseRoles&gt; section in the xml files in &lt;path_to_civicrm&gt;/templates/CRM/Case/xml/configuration. Depending on your version or upgrade history the xml definition might be in the civicrm_case_type table in the definition field.