Why are outgoing emails duplicated?

Question

PHP

There is BitrixVM, let's say at www.site-domain.ru. The problem occurs when sending mail using php send(). Letters are duplicated and some strange addresses are added to the copy ...
I do:

mail("[email protected]", "test", 'test', "From: [email protected]");

The letter comes to me from me, but for some reason, as it turned out. The same letter comes to the mail [email protected] Moreover, the recipients and senders remain the same. That is, this mailbox ([email protected]) is not listed among them, but only my [email protected] is registered. However, the following recipients were added to the copy:
1) [email protected]
2) [email protected]
In the logs, I see that it really sends a letter to [email protected] Before that, in the logs goes:
postfix/pickup[55145]: 01493634F5: uid=600 from=
postfix/cleanup[55154]: 01493634F5: message-id=<[email protected]>
postfix/smtp[55157]: warning: numeric domain name in resource data of MX record

Answer 1

Seems to understand. Partially :) Letters were copied to the mailbox. which was specified in sendmail_path, in the settings of the bitrix.env file. But I still don’t really understand the reason and where the addresses that are in the copy come from ...