Article report: Uncaught Error: Call to a member function getLocalizedTitle() on null

Hi,
We are running OJS 3.2.1.1 on RHEL7 with mysql 5.6
We are trying to run the Article Report in Report Generator for one of our journals but the report is empty. The error in the log is:
PHP Fatal error: Uncaught Error: Call to a member function getLocalizedTitle() on null in /path/plugins/reports/articles/ArticleReportPlugin.inc.php:128\nStack trace:\n#0 /path/lib/pkp/pages/management/PKPToolsHandler.inc.php(155): ArticleReportPlugin->display(Array, Object(Request))\n#1 /path/lib/pkp/pages/management/PKPToolsHandler.inc.php(58): PKPToolsHandler->report(Array, Object(Request))\n#2 /path/lib/pkp/classes/core/PKPRouter.inc.php(391): PKPToolsHandler->tools(Array, Object(Request))\n#3 /path/lib/pkp/classes/core/PKPPageRouter.inc.php(231): PKPRouter->_authorizeInitializeAndCallRequest(Array, Object(Request), Array, false)\n#4 /path/lib/pkp/classes/core/Dispatcher.inc.php(143): PKPPageRouter->route(Object(Request))\n#5 /path/lib/pkp/classes/core/PKPApplication.inc.php(279): Dispatcher->dispatch(Object(Request))\n#6 /journal-path/index.php(68) in /path/plugins/reports/articles/ArticleReportPlugin.inc.php on line 128, referer: https://journal/management/tools

This seems to related to this post: Article report failed - #5 by Daniel_delagarza

When I query “select * from submissions where section_id IS NULL” I get 128 rows.

However, many of these rows are for articles which were published in the most recent issue, and they appear in the appropriate sections. So how can they appear in the correct section if section id is NULL? And how can I correct this problem?

Thanks for any suggestions!

It turns out that the articles, although published, were assigned to a section which got deleted at some point in the past. Problem solved.