Gatling EL not working in extracting value from session attribute

I have a test that has a scenario with two executions.

  1. The first execution is a custom execution that I extended Gatling with
  2. The second execution is a standard http execution

What I want to do is set the return value from the first execution as a session attribute to be used in the second execution

The second execution looks like this

val sfViewGroupingCallExec = exec(http("ViewGrouping Call")

I can confirm that if I replace "${jwttoken}" with "${jwttoken.exists()}", 
then the call proceeds and  is working since I get a 401 response from the server as expected

However using "${jwttoken}"  in the header always gives me "No attribute named jwttoken" response.

I put a breakpoint as far as in NettyRequestSender to see what is the request on the wire and I see that the ${jwttoken} did resolve to a correct value.
So I am not sure why I am getting this error.