diff --git a/packages/core/src/Base/Traits/HasCustomerGroups.php b/packages/core/src/Base/Traits/HasCustomerGroups.php
index b88d78d9dc..bd2621ff8d 100644
--- a/packages/core/src/Base/Traits/HasCustomerGroups.php
+++ b/packages/core/src/Base/Traits/HasCustomerGroups.php
@@ -55,13 +55,14 @@ public function unscheduleCustomerGroup(
         );
     }
 
-    protected function validateScheduling(Collection $models)
+    protected function validateScheduling(Collection $models): bool
     {
         foreach ($models as $model) {
             if (is_object($model) && ! ($model instanceof CustomerGroup)) {
                 return false;
             }
         }
+        return true;
     }
 
     /**