Message disappears while forwarding

Question

gmail

Situation: there are three computers, all of them have MS Outlook 2007 and Kaspersky Anti-Spam configured in the same way.

The first one receives a seemingly ordinary letter with an attachment ... but you can’t see the original text of the letter. We forward the letter to the second.

There the letter opens and the source code can not be viewed either. We forward from the second to the third ...

... and the text of the letter disappears. Generally. There is an attachment, but the text is plain-text! - No. And when viewed through the Gmail web interface, the picture is the same.

For prevention, I ran it with antiviruses - no setups.
I save the letter on 2 computers as an eml file. In Outlook, its source cannot be viewed, as we remember. But if you open eml with Notepad, then the text of the letter is visible.
But on the 3rd computer, the same actions give only an attachment, there is no text.

Answer 1

With Kaspersky turned off, the same story happens. You can't try it on Thunderbird - there are computers on which it's better not to experiment :-)
But here's what I found after looking at the source code through the web interface:
The letter came from The Bat in Windows-1251 to mailbox 1, and it was edited in Outlook ...
On mailbox 2 for some reason, the letter arrived in KOI-8 R, and the one sent to 3 again ended up in Windows-1251.
I smell a bug with encodings, I feel it, but I can’t justify it :-)