GateIn is not under active development, I have not clear if what you try to perform is to fix your single CustomSingleSignOn mechanism.
I would recommend to try (if possible) with latest GateIn 3.8.16.Final I remember there were a lot of fixes and changes compared with GateIn 3.4 and probably things you try to work on are already there, or the 3.8.16.
But again, not active project and core developers are working in different projects.
Unfortunately we are using gatein 3.4 and that might be the problem. I am not trying to fix our SSO classes i just wanted to know how these two seperate applications request the same session. it could be mixed on gatein's own settings and our applications settings for session management when we started using gatein & that if somehow gatein has a mechanism to prevent these two applications to use different sessions for example ThreadLocalSessionProviderInitializedFilter (idk). Because of same thread on the same browser?
Yes, we plan to upgrade but i don't know exactly when.
Thanks for the response