When State is updated for task on Planning console: "Manual task constraint date can not be updated" error is thrownIssue When State is updated for task on Planning console: "Manual task constraint date can not be updated" error is thrownCauseError comes from ProjectWorkbenchPhaseValidationAndUpdate Business Rule. nav_to.do?uri=sys_script.do?sys_id=85005e90d713210058c92cf65e6103cf 'constraint_date' on Project Task is populated in engine code (JAVA).Out of the Box there is "Recalculate" Business Rule on Planned Task which will run for INSERT & UPDATE. The issue could be due to Recalculate Business Rule modified/customized or made inactive.ResolutionActivate the Out of the Box Recalculate Business Rule. If it has been customized, make sure it runs for both Insert and Update.