After upgrading to Kingston, an issue was found with the 'Planned duration' field on Project and Project Task forms, where it is calculating duration as Zero value.
On the Project Task Form, an issue is also observed with the Project End Date field, which is not taking the user input value. Hitting the Save button will revert back the End Date to either the start date or the current date value.
Release or Environment
First observed in Kingston Patch 4.
Customized Script Includes 'AjaxProjectTaskUtil' and 'ProjectTaskManagerUtil'.
Revert the Script Include 'ProjectTaskMangerUtil' to OOB.
If that does not fix the issue, check and revert if necessary the Script Include 'AjaxProjectTaskUtil'.