Do you have any other system or user plugins enabled that are meant to redirect the user? We just debugged another site where they had a 'jomsocialredirect' plugin which was bypassing our redirects.
Please check if that may be the case. Everything you show, and from looking at your site, looks correct...
Jomsocial is installed. Jomsocial redirect is not installed on the site. I searched for "redirect" and "login" in the extensions manager and did not find anything other than core joomla components.
Any other ideas?
Thank you so much for your help!