diff --git a/settings/controller/userscontroller.php b/settings/controller/userscontroller.php
index fed9e268a7c9e27035a9f17eda19f99f528f18cf..82483a76245a1f840a4aa841ab5dedf6d3330e5a 100644
--- a/settings/controller/userscontroller.php
+++ b/settings/controller/userscontroller.php
@@ -568,6 +568,7 @@ class UsersController extends Controller {
 		} else {
 			$groups = $this->groupManager->getSubAdmin()->getSubAdminsGroups($this->userSession->getUser());
 
+			$uniqueUsers = [];
 			foreach ($groups as $group) {
 				foreach($group->getUsers() as $uid => $displayName) {
 					$uniqueUsers[$uid] = true;