diff --git a/src/FieldStateManager.php b/src/FieldStateManager.php
index 9085ec4..5671ee9 100644
--- a/src/FieldStateManager.php
+++ b/src/FieldStateManager.php
@@ -203,7 +203,7 @@ class FieldStateManager extends DefaultPluginManager {
               t('Field States UI Issue Queue'),
               Url::fromUri('https://www.drupal.org/project/issues/field_states_ui')
             )->toString(),
-            '@details' => var_export(array_keys($element[0]),TRUE),
+            '@details' => var_export(array_keys($target),TRUE),
           ]
         )
       );