Hi Rohit,
We have provided the all grouping and filtering support for Tablix Report item. So, we are going to remove the Gird and Pivot Grid report item in our ReportDesigner control in upcoming Report Platform release and it is estimated to release on 2019 September first week . So, could you please use the Tablix report item instead of Pivot Grid as shown in below help documentation to avoiding the mentioned problem at your end.
Regards,
Vinoth S.