🇵🇰Pakistan @Khalid Ansari

I encountered the identical problem, which emerged from my attempt to modify the Drupal Commerce email builder class via hook_mailer_builder_info_alter. hook

In my custom module replaced $email_builders['commerce']['class'] with $email_builders['commerce_order_type']['class']

/**
 * Implements hook_mailer_builder_info_alter().
 */
function CUSTOM_MODULE_mailer_builder_info_alter(array &$email_builders) {
  $email_builders['commerce']['class'] = 'Drupal\CUSTOM_MODULE\Plugin\EmailBuilder\LegacyEmailBuilder';
  $email_builders['commerce_order_type']['class'] = 'Drupal\CUSTOM_MODULE\Plugin\EmailBuilder\LegacyEmailBuilder';
}

Khalid Ansari → made their first commit to this issue’s fork.