Ok, thanks for clarifying the problem. First, please check the "Returning User Redirection" setting in JFBConnect's Configuration area. It should be set to "Same Page" so that the user remains on the page they login in from.
If that setting is correct, we'll need to narrow down further. To do so, can you do the following:
* Log out of your site
* Disable the "Auto Login Facebook Users" setting
* Then, click a link from an email
* On the new page, you should not be logged in automatically (setting above disabled)
* Click the "Login with Facebook" button
* Let me know where that brings you...
If you stay on the same page, there may be an issue with the automatic login functionality.
If you're redirected, then something else is messing with the redirect URL and we'd have to investigate that further. In that case, can you let us know what kind of component you are sending user's to in your emails? Is that just a standard Joomla article or is it content from some other extension?
Sorry to answer your question with a lot more questions, but every detail helps us narrow things down.