TYPO3 Core

TYPO3 11.5.20
PHP 8.1.x

Happens for example BE-Module which uses:

$arrayPaginator = new ArrayPaginator($this->resultCures, $currentPage, $listNumber);
$paging = new SimplePagination($arrayPaginator);
$this->view->assignMultiple([
    'items' => $this->resultCures,
    'paginator' => $arrayPaginator,
    'paging' => $paging,
    'pages' => range(1, $paging->getLastPageNumber()),
]);

Core: Error handler (BE): PHP Warning: Undefined array key "hidden" in C:\MAMP\htdocs\typo3_sources\typo3_src-11.5.20\typo3\sysext\recordlist\Classes\RecordList\DatabaseRecordList.php line 1590

The $row in line 1590 contains only "uid" and "pid".

I think "if(isset($row[$hiddenField])) { ... }" should solve the problem.