There are two bugs I have found:
(1) Successful submit lacks a user confirmation action. I've tried both inline message and redirect to Wordpress Page. Nothing. The form just goes blank and that's it.
(2) Failed data validation does not properly show the field errors.
You can view the problem here (at least temporarily, until I close access).
Click on "Join the Email List" in the upper right corner. Double opt-in is activated. So you can simply disregard the confirmation email to avoid being added to the list.
Thanks for any help!