Hi,
I have noticed the same problem. I did some research and came to the conclusion that this only happens when the mail is encoded using "quoted-printable" encoding. In order for this happen, the mail needs to contain a special character that cannot be encoded using 7-bit encoding and therefore enforces "quoted-printable"-encoding. I have found that one can reproduce this phenomenon by sending a mail (using Apple Mail or also using an iPhone (I did it using the 3G)) that contains such a special character (e. g. 'ä') and does not have a terminating carriage return (one can avoid this problem by a starting a new line at the end of the mail).
I analyzed the source code of a mail which had this problem. It looked as follows (original content slightly changed (anonymization)):
From: John Doe <john.doe@johndoe.com>
Content-Type: text/plain; charset=iso-8859-1
Content-Transfer-Encoding: quoted-printable
Subject: Test
Date: Sun, 8 Aug 2010 19:00:24 +0200
Message-Id: <4873FCDE-5852-448F-2509-125845963FCD@gmail.com>
To: Smith Alex <alex.smith@alexsmith.com>
Mime-Version: 1.0 (Apple Message framework v1081)
X-Mailer: Apple Mail (2.1081)
This mail contains a special character =FC
John.=
As you can see, the mail is encoded using "quoted-printable" encoding and contains a '=' as ultimate character. When reading the RFC 2045 specification, one can see that an equal sign at this position is illegal. So it does not matter how it got there -- it should never be there.
Quote from the above mentioned document (
http://www.ietf.org/rfc/rfc2045.txt)
An "=" cannot be the ultimate or penultimate character in an encoded object. This could be handled as in case (2) above.
It seems to be a bug that some Apple e-mail clients appear to have.
Actually I just wanted to buy a Mac next week so I hope this will be fixed as soon as possible...
Cheers.
