Hello Adam,
This is a very unique occurance. Are you clicking "Back" to get to your form? Or refreshing the page?
When you visit the page with the form on it, it submits your email event? This sounds like you have custom Javascript in your "General Settings" of the Dynamic Forms Quick Menu. Can you please take a look at this area? Our module doesn't have a built in setting to allow you to send an email upon page load.
Thanks,
Ryan