diff --git a/typo3/sysext/indexed_search/Classes/Controller/AdministrationController.php b/typo3/sysext/indexed_search/Classes/Controller/AdministrationController.php
index 3c000e17308db5f61f984c45a1aa3e5d0092d58a..1066ec722aa2e3ac035cd4cfa841d96926ab5f61 100644
--- a/typo3/sysext/indexed_search/Classes/Controller/AdministrationController.php
+++ b/typo3/sysext/indexed_search/Classes/Controller/AdministrationController.php
@@ -307,7 +307,7 @@ class AdministrationController extends ActionController
             unset($debugInfo['lexer']);
         }
         $pageRecord = BackendUtility::getRecord('pages', $pageHashRow['data_page_id']);
-        $keywords = is_array($pageRecord) ? array_flip(GeneralUtility::trimExplode(',', $pageRecord['keywords'], true)) : [];
+        $keywords = is_array($pageRecord) ? array_flip(GeneralUtility::trimExplode(',', (string)$pageRecord['keywords'], true)) : [];
 
         $queryBuilder = GeneralUtility::makeInstance(ConnectionPool::class)->getQueryBuilderForTable('index_words');
         $wordRecords = $queryBuilder