Form submission with page ID doesn't appear as new contact on page performance



This contact has been created using the form API with a pageId in the context:

Here’s the performance graph on the corresponding page:

As you can see, the submission is recorded correctly and linked to the page.
But the contact isn’t in the “New contacts” count.
And once the contact becomes a customer, the “Customers” number doesn’t change either.

Why? Should we send more data to the form API?