Why do I get a second 'Submit' button after submitting form?

My form asks the user how they want to pay... PayPal or Check (see Page 4).  If the user selects PayPal, then the PayPal components are used on Page 7.  The user then clicks the Submit Membership button and is redirected to PayPal.  All works great!

However, if the user select Check, then I hide the PayPal components on the last page (Page 7).  The user clicks the Submit Membership button and is then presented with another page that I didn't create.  It has another Captcha entry and 'submit form' button.  If the user clicks this second 'submit form' button, then they do not go to PayPal and immediately redirected to my custom Thank You page.  This is all working great except for the second submission page.

Why is this second submission page showing up and how can I get rid of it?

You are hiding the required captcha field when "check" is selected, that's the reason why it redirects to the captcha page. Unfortunately, you can't skip required captcha even when hidden via condition, you will have to enter the captcha value.

Alternatively, you can replace the captcha field with Google reCaptcha. This works fine with conditions.