[BUGFIX] Prevent duplicate page renders on page not found ImmediateResponseExceptions

Classes/Controller/JoblistController.php

@@ -49,6 +49,7 @@ use TYPO3\CMS\Core\Country\CountryProvider;
 use TYPO3\CMS\Core\Error\Http\PageNotFoundException;
 use TYPO3\CMS\Core\Exception\SiteNotFoundException;
 use TYPO3\CMS\Core\Http\ImmediateResponseException;
+use TYPO3\CMS\Core\Page\PageRenderer;
 use TYPO3\CMS\Core\Resource\Exception\AbstractFileOperationException;
 use TYPO3\CMS\Core\Resource\Exception\ExistingTargetFileNameException;
 use TYPO3\CMS\Core\Resource\Exception\ExistingTargetFolderException;
@@ -304,6 +305,12 @@ class JoblistController extends ActionController {
 			$allJobsCount = $this->jobRepository->findJobsByFilter($filters)->count();
 			$numberOfPages = (int) ($jobLimit <= 0 ? 0 : \ceil($allJobsCount / $jobLimit));
 			if ($numberOfPages !== 0 && $currentPageBrowserPage >= $numberOfPages) {
+				/** @var PageRenderer $pageRenderer */
+				$pageRenderer = GeneralUtility::makeInstance(PageRenderer::class);
+				// the PageRenderer contains the content of the current request, the result of the following sub-request will
+				// be appended to it and we get 2 pages, the current one and the 404 page in one. We flush the PageRenderer
+				// content here, so it will contain only the 404 page content
+				$pageRenderer->setBodyContent('');
 				/** @var ErrorController $errorController */
 				$errorController = GeneralUtility::makeInstance(ErrorController::class);
 				$response = $errorController->pageNotFoundAction(