Not able to get the value of a expression rule using script task

Hi Appian  Pals, 
I have an expression rule which is calculating some data and that data is organized into a map and that list of map is being required to be called in a process variable.
In order to do this, I created a script task and then, I saved the output of this rule to a process variable and that variable is made using the required CDT.

The main issue is that the variable is not getting the value after the evaluation of the rule in the script task.
Can you please help me find a way through it?

Below is the output of that expression rule in the form of map. I have used the approach to calculate the value using refresh variables with refreshAlways:true


Below is the output of the process model where i have called this rule in the script task in the process model.


Below is the script task configuration:


Below is the process variable definition:


Below is the CDT that is used to create the above process variable:



Looking for a better guidance.

Thanks in advance..