diff --git a/tests/integration/features/bootstrap/FeatureContext.php b/tests/integration/features/bootstrap/FeatureContext.php
index 26db9d526fe..91c19ec45d4 100644
--- a/tests/integration/features/bootstrap/FeatureContext.php
+++ b/tests/integration/features/bootstrap/FeatureContext.php
@@ -903,7 +903,7 @@ protected function assertAttendeeList(string $identifier, ?TableNode $formData,
 				if (isset($attendee['actorId']) && str_ends_with($attendee['actorId'], '@{$REMOTE_URL}')) {
 					$attendee['actorId'] = str_replace('{$REMOTE_URL}', rtrim($this->remoteServerUrl, '/'), $attendee['actorId']);
 				}
-				if (preg_match('/^SHA256\(([a-z0-9@.+\-]+)\)$/', $attendee['actorId'], $match)) {
+				if (isset($attendee['actorId']) && preg_match('/^SHA256\(([a-z0-9@.+\-]+)\)$/', $attendee['actorId'], $match)) {
 					$attendee['actorId'] = hash('sha256', $match[1]);
 				}