I don't know if it's possible to have the email within a form / survey to be verified in real time once entered...
But allowing a form to be submitted (sending the user to the next step) while also having the email address fail verification and NOT proceed with adding the name to contacts etc. Causes a horrible user experience.
The user gets told their submission is completed etc on the next step, only to never receive an email confirmation or follow up etc.
Either email addresses need to be verified in real time (to let the user know their email address wont allow the form to be submitted)...
OR
The form submission should check if the email within has passed verification and IF it fails, the form should send the user back to the form page with a message that the email failed verification.