我有同样的问题！

FB PHP SDK将这些东西保存到$ _SESSION！
当您的用户点击退出时，您可以这样删除它们：

The FB PHP SDK saves those things into the $_SESSION! You can delete them like this when your user clicks logout:

$_SESSION['fb_'.APP_ID.'_user_id'] = '';
$_SESSION['fb_'.APP_ID.'_access_token'] = '';

虽然这不是最终的解决方案，但现在可以工作。

Although this is not the final solution, it works for now.

我感谢您的评论和解决方案！

I appreciate comments and solutions on that!