My form at http://www.metriquemarketing.com/index.php/contact/ redirects to index.php whenever the form is submitted. Even if all the required fields are incomplete, I never see any data entry errors. None of the confirmation settings (text / page / redirect) make any difference. Clicking submit does correctly submit to the database and generates e-mail but the user is sent to the home page in all cases.
I did deactivate my theme and all plug-ins and it made no difference. I should say the form worked as advertised before the recent update.