Munchkin associateLead didn't update user

I have an external form that I tie to Marketo through Munchkin code as below:

Munchkin.init('xxx-xxx-xxx');

Munchkin.munchkinFunction('visitWebPage', {url: '/r/2016-thank-you', params: 'registration=1'});

Munchkin.munchkinFunction('associateLead', {FirstName: '"' + $('#first').val() +'"', LastName: '"' + $('#last').val() +'"', Email: '"' + $('#email').val() +'"' }, data.token);

In addition, I have a smart campaign doing the following:

• on page view "/r/2016-thank-you"
  • add user to list
  • send user email confirmation

Here is the Problem

An existing cookied user in marketo e.g. "fred@gmail.com" filled out an external form (first, last, email). He used a different email "jdoe@gmail.com" (along with a different name: john, doe) while filling out the form. Instead of the following happening:

1. The user info: first, last, email gets updated
2. That updated info gets added to list
3. That updated email receives the confirmation email

Here is what actually happened:

1. The user info: first, last, email was NOT updated
2. The original info gets added to the list
3. The original email receives the confirmation email

What is the problem, and how to fix?

Thanks ~