Your problem sounds familiar. In the browsers memory the ticket to the backend is still available after logoff, right?
After logging off from the portal, you will need to login to the java stack (portal). This will work with a different user. But when you go to a webdynpro abap application, the old user information is displayed (meaning a privacy risk!).
The only thing I can think of is closing the browser before logging in again. There is no function in javascript to clear the browser cache unfortunately.
In another reply I read something about two different backend systems. It is strange that the problem does not occur on the old system, meaning this isn't a browser issue...
Sounds like a SSO misconfiguration indeed.
