Issue Rewrite headers in outgoing mail messages does not work properly

[Hausherr]

Server operating system version

Debian 11

Plesk version and microupdate number

18.0.41

The article at https://support.plesk.com/hc/en-us/...-to-rewrite-headers-in-outgoing-mail-messages describes how to modify outgoing messages from the header in Postfix. Since the entry is made directly in main.cf, this configuration also applies to incoming messages. But this should not be so, because it distorts incoming messages. What must the configuration look like so that it only takes effect for outgoing and not also incoming mails?

Also missing is the hint that the postfix-pcre package must be installed, at least under Debian 11.