well! At last i solved my issue deleting part of code for login through Jomsocial on homepage.
At that point manual login was working but login with facebook still have same problem (log out after browser closing also if session was still open).
So i ran autotune and at SITE CHECK there was a warning that another app was using FB Javascript.
I disabled EVERYTHING in jomsocial facebook integration and set everything on NO
Now Jfbconnect work great and Sclogin too.. after i close browser i'm still logged.
Consider to check this issue about jomsocial because i noticed that you was really happy about this integration jfbconnect/jomsocial.. but for me right now was doing only trouble.
Maybe is only issues regarding me... but just in case .. give a look. I'm satisfacted enough with only Jfbconnect that seems stable and functional