diff --git a/core/themes/claro/claro.theme b/core/themes/claro/claro.theme
index 5916898c02c8bd99e8308fc6c3e4534625db3633..ba41e6d7c86c95354a5e8442404c7580f2a53074 100644
--- a/core/themes/claro/claro.theme
+++ b/core/themes/claro/claro.theme
@@ -747,10 +747,12 @@ function claro_form_system_modules_alter(&$form, FormStateInterface $form_state)
       foreach (Element::children($form['modules'][$key]) as $module_key) {
         if (isset($form['modules'][$key][$module_key]['links'])) {
           foreach ($form['modules'][$key][$module_key]['links'] as $link_key => &$link) {
-            $action_link_type = $link_key_to_action_link_type[$link_key];
-            $link['#options']['attributes']['class'][] = 'action-link';
-            $link['#options']['attributes']['class'][] = 'action-link--small';
-            $link['#options']['attributes']['class'][] = "action-link--icon-$action_link_type";
+            if (array_key_exists($link_key, $link_key_to_action_link_type)) {
+              $action_link_type = $link_key_to_action_link_type[$link_key];
+              $link['#options']['attributes']['class'][] = 'action-link';
+              $link['#options']['attributes']['class'][] = 'action-link--small';
+              $link['#options']['attributes']['class'][] = "action-link--icon-$action_link_type";
+            }
           }
         }
       }