When using prefill, the form submission isn't linked to the same contact (guid) on form submission.

For example, when you a) add [contact @ email. com] with guid123 to a segment b) send an email to that segment c) that contact clicks on the email link & submits a form d) a duplicate contact@email.com with guid345 gets updated & linked in the form submission. 

Please create a way to ensure guid123 is linked in the form submission, not guid345.