我遇到了同样的问题，但在设置新会话变量之前调用 clear 方法解决了这个问题.

I had the same problem, but calling the clear method before setting a new session variable fixed the problem.

    $session = & JFactory::getSession();
    /* this way unset data from the session store */
    $session->clear('security_code');
    /* and now set the new value */
    $session->set('security_code', $code);

即使是您第一次声明会话变量也能正常工作.

It works even if is the first time you are declaring a session variable.