diff --git a/apps/comments/lib/Collaboration/CommentersSorter.php b/apps/comments/lib/Collaboration/CommentersSorter.php
index 46fec87c777..faecc1f7a47 100644
--- a/apps/comments/lib/Collaboration/CommentersSorter.php
+++ b/apps/comments/lib/Collaboration/CommentersSorter.php
@@ -26,6 +26,10 @@ class CommentersSorter implements ISorter {
 	 * @param array $context
 	 */
 	public function sort(array &$sortArray, array $context): void {
+		if (!isset($context['itemType'], $context['itemId'])) {
+			return;
+		}
+
 		$commenters = $this->retrieveCommentsInformation($context['itemType'], $context['itemId']);
 		if (count($commenters) === 0) {
 			return;