diff --git a/authcache.module b/authcache.module
index f16cdfe..fcc0bb9 100644
--- a/authcache.module
+++ b/authcache.module
@@ -337,7 +337,7 @@ function authcache_form_value_suspect(&$element, $form_id, $parents = array()) {
   }
 
   foreach (element_children($element, FALSE) as $key) {
-    authcache_form_value_suspect($element[$key], $form_id, array_merge($parents, array($key)));
+    authcache_form_value_suspect((array) $element[$key], $form_id, array_merge($parents, array($key)));
   }
 }