Your mail is dropped for internal error.

[Vladislav Tchernev]

Hello All,
I started receiving mail which body has been replaced with:
Your mail remote_mta_IP:Port->my_mailserver_IP:25 is dropped for internal error.

Some of our clients are reporting that they have received emails with
a similar body from us as well.
When I trace my postfix and amavis log for those emails they does not
show any errors and still the body somehow is being modified.
Tried to find something related on the net but got just couple of
similar cases without resolution. Any ideas?

Thanks!
Vlad