Warning: Undefined array key "required" in /var/www/clients/client1/web4/web/lib/pkp/classes/submission/GenreDAO.php on line 251

Fatal error: Uncaught TypeError: PKP\submission\Genre::setRequired(): Argument #1 ($required) must be of type bool, null given, called in /var/www/clients/client1/web4/web/lib/pkp/classes/submission/GenreDAO.php on line 251 and defined in /var/www/clients/client1/web4/web/lib/pkp/classes/submission/Genre.php:213 Stack trace: #0 /var/www/clients/client1/web4/web/lib/pkp/classes/submission/GenreDAO.php(251): PKP\submission\Genre->setRequired() #1 /var/www/clients/client1/web4/web/lib/pkp/classes/db/DAOResultFactory.php(135): PKP\submission\GenreDAO->_fromRow() #2 /var/www/clients/client1/web4/web/lib/pkp/classes/db/DAOResultFactory.php(233): PKP\db\DAOResultFactory->next() #3 /var/www/clients/client1/web4/web/pages/issue/IssueHandler.php(343): PKP\db\DAOResultFactory->toArray() #4 /var/www/clients/client1/web4/web/pages/issue/IssueHandler.php(132): APP\pages\issue\IssueHandler::_setupIssueTemplate() #5 [internal function]: APP\pages\issue\IssueHandler->view() #6 /var/www/clients/client1/web4/web/lib/pkp/classes/core/PKPRouter.php(334): call_user_func() #7 /var/www/clients/client1/web4/web/lib/pkp/classes/core/PKPPageRouter.php(278): PKP\core\PKPRouter->_authorizeInitializeAndCallRequest() #8 /var/www/clients/client1/web4/web/lib/pkp/classes/core/Dispatcher.php(165): PKP\core\PKPPageRouter->route() #9 /var/www/clients/client1/web4/web/lib/pkp/classes/core/PKPApplication.php(395): PKP\core\Dispatcher->dispatch() #10 /var/www/clients/client1/web4/web/index.php(21): PKP\core\PKPApplication->execute() #11 {main} thrown in /var/www/clients/client1/web4/web/lib/pkp/classes/submission/Genre.php on line 213