After having deleted all reports of a tracker, you can create a new empty one. If you try to add a new table to this report you will get this error

Fatal error: Uncaught Error: Typed property Tracker_Report_RendererFactory::$report_session must not be accessed before initialization in /usr/share/tuleap/plugins/tracker/include/Tracker/Report/Tracker_Report_RendererFactory.php:285 
Stack trace: 
#0 /usr/share/tuleap/plugins/tracker/include/Tracker/Report/Tracker_Report.php(1334): Tracker_Report_RendererFactory->createInSession() 
#1 /usr/share/tuleap/plugins/tracker/include/Tracker/Report/Tracker_Report.php(1496): Tracker_Report->addRendererInSession() 
#2 /usr/share/tuleap/plugins/tracker/include/Tracker/TrackerManager.php(144): Tracker_Report->process() 
#3 /usr/share/tuleap/plugins/tracker/include/Tracker/TrackerManager.php(179): TrackerManager->processSubElement() 
#4 /usr/share/tuleap/plugins/tracker/include/TrackerPluginDefaultController.php(45): TrackerManager->process() 
#5 /usr/share/tuleap/src/common/Request/FrontRouter.php(250): Tuleap\Tracker\TrackerPluginDefaultController->process() 
#6 /usr/share/tuleap/src/common/Request/FrontRouter.php(108): Tuleap\Request\FrontRouter->routeHandler() 
#7 /usr/share/tuleap/src/www/index.php(50): Tuleap\Request\FrontRouter->route() 
#8 {main} thrown in /usr/share/tuleap/plugins/tracker/include/Tracker/Report/Tracker_Report_RendererFactory.php on line 285