TGV Parameters Filtering doesn't show record if value is blank

Hello All,

I have created TGV on part and I have added parameters to search and filter on  custom "state" property . I have given default value as * .

It works well and able to search and filter on state column but there is one issue if any record has state "Blank" . That record is skipped from TGV results and which is causing me showing incorrect TGV results .

Help me to understand cause.

Thanks in advance .