If you are not able to see a preview of your imported preset of essential grid, please go to

../plugins/essential-grid/admin/assets/js/

and open file

admin.js

You should see this code between lines 971 and 973

}catch(e){ // 971 row
continue; //invalid json
} // 973 row

Instead of that code, please insert this one

}catch(e){ // 971 row
try{
value = t.stripslashes(value);
var json_array = jQuery.parseJSON(value);
}catch(e){
continue; //invalid json
}
} // 978 row

Here is a diff