We are facing a very peculiar issue for the first ever login of any operator (we are using Webseal SSO authentication)

When any user is logging for first time, his OperatorID details are visible till Application header.
Inside application BODY however none of his details are getting stored. If the user logs out and logs in, then it is fine.
If we see clipboard, the OperatorID page with all details are present. In Remote trace, we are observing that OPeratorID page has values only till Header.
Once the application BODY loads, the OperatorID page is empty. (We tested this by calling a common DT inside a layout in Header as well as application BODY).
If the user logs out of application and logs in again, this issue no longer appears. This issue happens to every user for first time login of that particular operator id only.

Please note our Portal contains a Screen Layout: with Header and BODY
The BODY (inside which OperatorID page details are empty) contains a Dynamic Container (Mode - MultiDocument (16))

If we change the Document mode inside the Dynamic Container from Multi to Single Mode and check the uselegacy iFrameMode then the issue is resolved.
However this is not a recommended approach as we are unable to open multiple documents.
PRPC version - 7.3.1

***Edited by Moderator Marissa to update platform capability tags****