TYPO3 Undefined array key 1 – PHP Versions

I have an extbase extension. If I add a new item then I see this error:

PHP Warning: Undefined array key 1 in
/var/www/html/typo3/typo3_src-11.5.13/typo3/sysext/extbase/Classes/Routing/ExtbasePluginEnhancer.php line 202

My method:

public function listAction(): ResponseInterface
{
    // List
    if ($this->settings['display'] == '0') {
        if ($this->settings['categories'] != '') {
            if ($this->settings['important'] != '0') {
                $articles = $this->getImportantFromCategories();
            } else {
                $articles = $this->getFromCategories();
            }
        } else {
            if ($this->settings['important'] != '0') {
                $articles = $this->getImportantArticles();
            } else {
                $articles = $this->getArticles();
            }
        }
    }
    // Archive
    if ($this->settings['display'] == '2') {
        $articles = $this->getArchivedArticles();
    }
    // If not details
    if ($this->settings['display'] != '1') {
        // Pagination
        $articlesArray = $articles->toArray();
        $currentPage = $this->request->hasArgument('currentPage') ? $this->request->getArgument('currentPage') : 1;
        $paginator = new ArrayPaginator($articlesArray, intval($currentPage), intval($this->settings['perpage']));
        $simplePagination = new SimplePagination($paginator);
        $articles = $this->articleRepository->findAll();
        $this->view->assignMultiple(
            [
                'articles' => $articles,
                'paginator' => $paginator,
                'pagination' =>
                    [
                        'lastPageNumber' => $simplePagination->getLastPageNumber(),
                        'firstPageNumber' => $simplePagination->getFirstPageNumber(),
                        'nextPageNumber' => $simplePagination->getNextPageNumber(),
                        'previousPageNumber' => $simplePagination->getPreviousPageNumber(),
                        'startRecordNumber' => $simplePagination->getStartRecordNumber(),
                        'endRecordNumber' => $simplePagination->getEndRecordNumber(),
                        'currentPageNumber' => $paginator->getCurrentPageNumber(),
                        'pages' => $simplePagination->getAllPageNumbers(),
                        'article_counter' => $this->article_counter,
                    ],
                'article_counter' => $this->article_counter,
            ]
        );
    }
    return $this->htmlResponse();
}

and the getArticles() method:

public function getArticles()
    {
        $table = 'tx_extension_domain_model_article';
        $query = $this->articleRepository->createQuery();
        if ($this->settings['sorting'] == 'list') {
            $query->statement('SELECT * FROM ' . $table . ' WHERE archived != 1');
        } else {
            $query->statement('SELECT * FROM ' . $table . ' WHERE archived != 1 ORDER BY crdate DESC');
        }
        $this->article_counter = $query->count();
        return $query->execute();
    }

I don’t know why this error message is triggered.

The only change is the PHP Version from 7.4 to 8.0.21.

My route enhancer

routeEnhancers:
  Plugin:
    type: Extbase
    extension: Plugin
    plugin: News
    routes:
      - routePath: '/{slug}'
        _controller: 'Article::show'
        _arguments:
          slug: article
      - routePath: '/page/{page}'
        _controller: 'Article'
        _arguments:
          page: currentPage
    defaultController: 'Article::list'
    requirements:
      slug: '^[a-zA-Z0-9].*$'
      page: 'd+'
    aspects:
      slug:
        type: PersistedAliasMapper
        tableName: tx_extension_domain_model_article
        routeFieldName: slug
      page:
        type: StaticRangeMapper
        start: '1'
        end: '100'