How to properly configure sending mail to cron for multisite?

Question

1C-Bitrix

Hello!

Input data:
VM Bitrix - 7.4.12
Main site - ext_kernel (site_master)
Additional site (mirror) - link (site_mirror) to the main one, one database, etc., minor visual changes.

Extract from dbconn.php

...
define("BX_CRONTAB_SUPPORT", true);
...

.msmtprc config

# smtp account configuration for site_master
account site_master
logfile /home/bitrix/msmtp_site_master.log
host smtp.yandex.ru
port 587
from почта@некий_домен
aliases /etc/aliases
keepbcc off
auth on
user некий_пользователь
password некий_пароль

tls on
tls_certcheck off
tls_starttls on

# smtp account configuration for site_mirror
account site_mirror
logfile /home/bitrix/msmtp_site_mirror.log
host smtp.yandex.ru
port 587
from почта@некий_домен
aliases /etc/aliases
keepbcc off
auth on
user некий_пользователь
password некий_пароль

tls on
tls_certcheck off
tls_starttls on

From the Apache config, for the second site it is similar, only the site_mirror config is called

<Directory /home/bitrix/ext_www/site_master>
    ...
    php_admin_value sendmail_path "msmtp -t -i -a site_master"
    ...
  </Directory>

The default cron config for the main site.

Problem:
Email from site_mirror is not sent to cron. If you send a letter from the main site, then you will receive a letter from the main site and a letter that was previously "sent" from the mirror.

It works on hits from both sites.

Where do you need to dig?