What are you using for SEF URLs or to restrict that content? Normally, when you are redirected to a Login page, there is a return=(some really long string) parameter in the URL, like:
index.php?option=com_users&view=login&Itemid=159&return=L2luZGV4LnBocD9vcHRpb249Y29tX2NvbnRlbnQmYW1wO3ZpZXc9YXJ0aWNsZSZhbXA7aWQ9OTpjaG9vc2luZy1hLWpvb21sYS1mYWNlYm9vay1leHRlbnNpb24mYW1wO2NhdGlkPTgmYW1wO0l0ZW1pZD0xNTk=
If the redirect occurs that way, JFBConnect will properly redirect the user back to the originating article. Adding that return=... paramater is the normal way for Joomla to redirect the user to a login form.
Can you try disabling your SEF URLs or whatever your using to do that redirect and test again and see if it works? You don't have to disable them permanently, but knowing if that helps fix the problem will help us understand what the issue is and how to fix it.
Thanks,
Alex