Bitrix24. Incoming letter. Why is a new contact created?

Question

Bitrix24

Hello. Who faced such a question. With an incoming letter, a new contact is constantly created. For the test, they sent from the same mailbox.
All checkboxes in the mail settings are turned off. Only one is written "Create a new lead for each new incoming letter from the specified" addressees. But as it is said from the quotes " Create a new lead ... " but not a contact.

Answer 1

repeat leads, BP for creating a lead, event handlers, external applications - many factors and their combinations besides your checkboxes.

Answer 2

Why are the addresses given? Since different requests could come from one incoming mail, it is necessary that each request be recorded separately. If we remove it from the list, there will be confusion in requests, since Bitrix will attach each letter with an open transaction.