The following error is reproduceable on a fresh install of CiviCRM 5.35.1 on WordPress 5.7. If self-service cancellation is enabled for a simple event, the cancellation or transfer request results in the following error:
CRM_Core_Exception: getFieldValue failed in /home/bbcadmin2016/sigstage57.net/wp/wp-content/plugins/civicrm/civicrm/CRM/Event/Form/SelfSvcUpdate.php on line 132
The stack trace indicates this:
CRM_Core_DAO::getFieldValue('CRM_Event_DAO_Ev…', null, 'title') /home/bbcadmin2016/sigstage57.net/wp/wp-content/plugins/civicrm/civicrm/CRM/Event/Form/SelfSvcUpdate.php:132
I am reporting this again in the hope that it can be verified by someone else as a bug - something that the core team requests before submitting the issue.