Exception in Demo Module Event Registration

Problem/Motivation

Saving the build elements throws the exception:

Drupal\webform\WebformException: The Demo: Event Registration webform [demo_event_registration] has overridden settings and/or properties and can not be saved. in Drupal\webform\Entity\Webform->preSave() (line 2312 of /var/lib/tugboat/stm/web/modules/contrib/webform/src/Entity/Webform.php).

Steps to reproduce

- launch a test environment on simplytest.me for Drupal 9.5.8
- add module webform and (under advance section) module token
- enable "Webform Demo: Event Registration System" (and related modules) from the section "Webform Demo"
- navigate to the webform: /admin/structure/webform/manage/demo_event_registration
- hit the button "Save elements"
- check watchdog: there is the exception mentioned above
- navigate to the webform handlers: /admin/structure/webform/manage/demo_event_registration/handlers
- DISABLE handler "Submission limit"
- navigate back to the webform an save the elements again: no exception, elements were saved

Additional Information

- tested locally with php versions 7.4 8.0 8.1 => error occurs on all versions