diff --git a/lib/GroupManager.php b/lib/GroupManager.php
index c530c5ed..28bd652f 100644
--- a/lib/GroupManager.php
+++ b/lib/GroupManager.php
@@ -70,7 +70,7 @@ public function __construct(
 	private function getGroupsToRemove(array $samlGroupNames, array $assignedGroups): array {
 		$groupsToRemove = [];
 		foreach ($assignedGroups as $group) {
-			if (in_array($group->getGID(), $samlGroupNames)) {
+			if (in_array($group->getGID(), $samlGroupNames, true)) {
 				continue;
 			}
 			// if group is not supplied by SAML and group has SAML backend