Form submissions from two people merged into one contact

Hi everyone,

I’m running event registrations via a HubSpot form (let’s call it Form X). The form collects first name, last name, company name, email address, and a few other fields. I then built an active list (List Y) with the filter “Contact has filled out Form X” to drive a follow-up email campaign.

Here’s the issue:

- The form shows 580 submissions, but the active list contains only 480 contacts. I’ve excluded obvious cases like duplicate submissions by the same person or submissions where one email was used to register multiple colleagues.

There’s still a “gap” — some people who submitted the form are missing from the list. A specific case that illustrates the problem:

Two people from the same company registered within minutes of each other (initials SH and TK).

- First, SH submitted the form using their own company email (S.H@company.com).

- 5 minutes later, TK submitted the form using their own company email (T.K@company.com)

- In the Form submissions view, I see two entries, but both show TK’s first/last name (while the detail view for each submission shows the form field values correctly).

- When I click “View” from the submissions list to open the contact, it always takes me to the same contact record: TK.

- I cannot find a separate contact for SH at all - searching by SH’s email returns TK’s record. SH is not present in List Y and did not get any follow-up or confirmation. SH is also missing from the workflow’s enrollment history.

- When I export all form submissions to Excel, the form field values (first/last name and email) are correct for both SH and TK (two different people, two different emails). However, the contact properties (Contact first name/last name/email) are the same for both rows and correspond to TK.

My hypotheses and questions:

1) It looks like HubSpot associated both submissions to a single contact based on the same browser cookie (perhaps they used the same device), and then updated the existing contact with the second submission’s email - effectively overwriting/merging the first person (SH) into TK’s record. Is that the expected behavior when the form is submitted from the same device with a different email, unless “Always create contact for new email address” is enabled in the form options?

2) Would enabling “Always create contact for new email address” on Form X prevent this in the future, ensuring that a new contact is created when a different email is submitted on the same device?

3) Are there any additional best practices you recommend for shared devices that reduce the chance of overwriting contacts?

4) Regarding the 580 vs. 480 discrepancy: I understand that lists show unique contacts while the forms tool shows total submissions, so multiple submissions may collapse into fewer contacts.

Are there any other common factors that could reduce the list count, even when the list’s only visible filter is “Filled out form is any of Form X”? How can I make sure I send the follow-ups to all of the registered people?

What I’ve already done:

- Confirmed that the exported form field values have two distinct people and emails.

- Verified that SH does not appear in Contacts or the workflow enrollment history.

- Observed that clicking from the submission record always opens TK’s contact.

If anyone has seen this and can confirm the cookie-based behavior and the impact of the “Always create contact for new email address” setting - or if there are additional hidden gotchas I should be aware of - I’d appreciate your guidance!

Thank you!!!

Hi @JHewusz,

Happy to help here - you’re on the right track.

  1. That’s correct and it is best practice to enable the “Always create…” option. Besides using the same device, registering through a marketing email forwarded by someone else can also cause this, as marketing email links are personalized in HubSpot by default.
  2. Yes.
  3. Point out on the registration page that each registrant should use a separate email. Sometimes contacts use the same info@ address for multiple people, believing that will serve the same purpose.
  4. No - unless the same person registered multiple times, the auto-merge is likely the main and only reason here.

Best regards!

Hi Karsten,
your explanation fully aligns with what I suspected.

Thanks for the explanation, clear guidance and best practices!

Best regards,
Julia

Since SH and TK used the same browser, HubSpot’s tracking cookie assumed it was the same person just updating their details, which is why SH’s record was effectively overwritten and why your contact count doesn’t match the submission count. To fix this, just toggle on the “Always create contact for new email address” setting in your form options; that forces HubSpot to treat every unique email as a new lead, regardless of the device. At Devlixor Technologies, we actually run into this quite a bit when engineering growth systems for our global clients, so we usually set up an n8n automation layer to pipe raw submissions into a separate database as a “source of truth” backup. It’s a great way to ensure 100% data integrity and avoid these native CRM quirks. Hope that helps!