The sitemap is not just seen blank.. it is throwing an error:
[23-Nov-2021 16:37:57 UTC] PHP Warning: require(/var/www/project/web/app/plugins/autodescription/inc/classes/builders/sitemap-base.class.php): failed to open stream: No such file or directory in /var/www/project/web/app/plugins/autodescription/bootstrap/load.php on line 160
[23-Nov-2021 16:37:57 UTC] PHP Fatal error: require(): Failed opening required '/var/www/project/web/app/plugins/autodescription/inc/classes/builders/sitemap-base.class.php' (include_path='.:/usr/share/php') in /var/www/project/web/app/plugins/autodescription/bootstrap/load.php on line 160
This is happening only after upgrading to 4.2.0.