This issue is with the "sn-record-picker" directive in the Service Portal. When you try and include a reference field (such as "department") in the "display-fields" parameter, the field that you specify doesn't render. When you include a non-reference field in the "display-fields" parameter (such as "user_name"), the widget renders as you would expect.

1. Create a new blank widget in the Service Portal
2. Replace the HTML Template with the contents from large_shopping_cart OOB:

   <div>
   <sn-record-picker field="" table="'sys_user'" display-field="'name'" display-fields="'user_name'" value-field="'sys_id'" search-fields="'name'" page-size="100" ></sn-record-picker>
   </div>

   large_shopping_cart Angular ng-template OOB:

   https://<instance-name>.service-now.com/sp_ng_template.do?sys_id=8a237cd06701220023c82e08f585ef98&sysparm_record_list=&sysparm_record_target=sp_ng_template&sysparm_record_row=11&sysparm_record_rows=15

3. Save the widget and preview it.
4. Note that the "user_name" field is displayed below the name of the user in the record picker.
5. Replace the HTML Template with:

   <div>
   <sn-record-picker field="c.requestedFor" table="'sys_user'" display-field="'name'" display-fields="'department'" value-field="'sys_id'" search-fields="'name'" page-size="100" ></sn-record-picker>
   </div>

6. Save the newly modified widget and preview it.
7. Note that the "department" field does not display below the name of the user in the record picker

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