Hi Anis,
Thanks for contacting Syncfusion support.
We have checked the mentioned parameter problem with our latest Essential studio build version (15.4.0.17) and its working properly at our end. We suspect the mentioned problem might have occurred due to when the hidden parameter is used for the parameter layout. So, can you please share the RDL report file to validate the mentioned problem at our end.
For your reference, we have prepared a sample and it can be downloaded from below location,
Regards,
Yuvaraj D.