Looks like the same issue affecting T337550: thank you failmail: UNKNOWN HTML rendering of template failed
Log output:
2023-05-25 17:20:04,324 INFO civicrm.wmf.INFO: wmf_civicrm: Converting to settlement currency: CZK -> USD 2023-05-25 17:20:04,822 ERROR PHP Warning: include(/srv/org.wikimedia.civicrm-files/civicrm/templates_c/en_US/%%CC/CCD/CCD559CC%%string%3A%7Beval+var%3D%24smartySingleUseString%7Csmarty%3Anodefaults%7D.php): failed to open stream: No such file or directory in /srv/org.wikimedia.civicrm/drupal/sites/all/modules/civicrm/packages/Smarty/Smarty.class.php on line 1273 2023-05-25 17:20:04,823 ERROR PHP Warning: include(): Failed opening '/srv/org.wikimedia.civicrm-files/civicrm/templates_c/en_US//%%CC/CCD/CCD559CC%%string%3A%7Beval+var%3D%24smartySingleUseString%7Csmarty%3A nodefaults%7D.php' for inclusion (include_path='/srv/org.wikimedia.civicrm/drupal/sites/all/modules/civicrm/ext/civiimport/:/srv/org.wikimedia.civicrm/drupal/sites/default/civicrm/extensions/damaged/:/srv/org.wi kimedia.civicrm/drupal/sites/all/modules/civicrm/ext/authx/:/srv/org.wikimedia.civicrm/drupal/sites/all/modules/civicrm/ext/oauth-client/:/srv/org.wikimedia.civicrm/drupal/sites/all/modules/civicrm/ext/flexmaile r/:/srv/org.wikimedia.civicrm/drupal/sites/all/modules/civicrm/ext/message_admin/:/srv/org.wikimedia.civicrm/drupal/sites/default/civicrm/extensions/uk.squiffle.assignee/:/srv/org.wikimedia.civicrm/drupal/sites/ all/modules/civicrm/ext/legacycustomsearches/:/srv/org.wikimedia.civicrm/drupal/sites/default/civicrm/extensions/monolog/:/srv/org.wikimedia.civicrm/drupal/sites/all/modules/civicrm/ext/recaptcha/:/srv/org.wikim edia.civicrm/dr in /srv/org.wikimedia.civicrm/drupal/sites/all/modules/civicrm/packages/Smarty/Smarty.class.php on line 1273 2023-05-25 17:20:04,921 INFO civicrm.wmf.INFO: wmf_common: Aborting DB transaction. 2023-05-25 17:20:04,955 INFO civicrm.wmf.ERROR: wmf_common: Failure while processing message: UNKNOWN HTML rendering of template failed in cs.