Comment 10 for bug 411358

This is a plain text message. Even the email from bugzilla (your comment) triggered this bug. And in safe mode, all plugins are disabled. I also tried to manually disable all plugins that I use.
I removed some more characters from the string and this is the shortest string that I found:

T+08:0

The source of a test message:

FCC: imap://greenpeak%<email address hidden>/INBOX
X-Identity-Key: id8
Message-ID: <email address hidden>
Date: Tue, 14 Sep 2010 09:30:03 +0200
From: Theo Band <email address hidden>
X-Mozilla-Draft-Info: internal/draft; vcard=0; receipt=0; DSN=0; uuencode=0
User-Agent: Mozilla/5.0 (X11; U; Linux i686 (x86_64); en-US; rv:1.9.2.9) Gecko/20100825 Lightning/1.0b2 Thunderbird/3.1.3
To: test
Subject: test
X-Enigmail-Version: 1.1.1
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 7bit
MIME-Version: 1.0

(GMT+08:00)