Text/plain attachments instead of mail body

Hi all,
I am seeing a strange behaviour of RT (3.8.4, but I’m seeing this since out first installation which was 3.8.2).
I found other reports of this behaviour, but all were very old threads.

Here it is: when someone sends a mail with a text/plain attachment, I see it correctly in RT; but then RT triggers an email to AdminCCs notifying them of the new ticket. Well, the latter email contains the original attachment as body, and it contains the original text as an html attachment.

Does anybody else see this behaviour?