diff --git a/lib/private/Comments/Comment.php b/lib/private/Comments/Comment.php
index 136504de3066c..597d83ec72401 100644
--- a/lib/private/Comments/Comment.php
+++ b/lib/private/Comments/Comment.php
@@ -209,6 +209,8 @@ public function getMentions(): array {
 			if (str_starts_with($cleanId, 'guest/')) {
 				$result[] = ['type' => 'guest', 'id' => $cleanId];
 			} elseif (str_starts_with($cleanId, 'email/')) {
+				/** @var non-empty-lowercase-string $cleanId */
+				$cleanId = substr($cleanId, 6);
 				$result[] = ['type' => 'email', 'id' => $cleanId];
 			} elseif (str_starts_with($cleanId, 'federated_group/')) {
 				/** @var non-empty-lowercase-string $cleanId */