I'm unsure why you'd see that behavior. Could you try to setup a standard Joomla mod_login module and configure the login redirect the same in that module as you have in SCLogin. Then, test to see if has the same issue. If so, that means that the issue is an underlying Joomla issue. If not, then it may be an issue with the SCLogin module.
Let us know how that test goes. If it still fails, it'd be very helpful to see the mod_login and SCLogin module on the same page somewhere so we can see the HTML and understand the difference.
Thanks,
Alex