Project task not saving in the Planning Console - Error message "Cannot read property 'isAfter' of undefined"DescriptionAfter creating a child task in the Planning Console for a project, it might not be possible to move it up or down; the page stays on a loading page and never saves. While no errors are logged on the System Logs, the following error can be seen on the browser console: TypeError: Cannot read property 'isAfter' of undefined at js_includes_gantt.js:22925 at PWGanttTask.eachParent (js_includes_gantt.js:19023) at refreshParents (js_includes_gantt.js:22847) at refreshData (js_includes_gantt.js:22833) at ClientSidePCService.executeGantt (js_includes_gantt.js:22385) at eval (planning-console.js:172) at Scope.$broadcast (js_includes_sp_libs.jsx?v=06-05-2020_2026&lp=Tue_Jun_16_20_17_52_PDT_2020&c=24_785:14925) at deleteHandler (js_includes_gantt.js:14256) at Object.callback (js_includes_gantt.js:14273) at Scope.ok (js_includes_gantt.js:25477)(anonymous) @ js_includes_sp_libs.jsx?v=06-05-2020_2026&lp=Tue_Jun_16_20_17_52_PDT_2020&c=24_785:12321Release or EnvironmentAll releases.CauseSome Project Tasks that are in Closed Complete state have an empty 'Actual End Date' [work_end].ResolutionSuch Project Tasks should be amended by adding a value for their 'Actual End Date' [work_end] field.Please note that updating this field from the front end might not be possible; if that's the case, such records should be updated via background script or export/import XML.