trouble syncing mail copied in local repository

[Campbell Brown]

I have recently started using offlineimap. I am using 6.5.6 from the
Arch repository (when I run offlineimap --version it reports 6.5.5, but
I believe that is another small bug?) I am syncing two email accounts:
one is Gmail, the other is Exchange (provided by my work). Gmail is
fine, but I'm having a problem with the Exchange account.

The problem is as follows:

- I copy a message in my local mail repository (using mutt), and then
	sync mail using offlineimap.

- The copied message is synced, but does not display correctly in other
	clients, e.g., Thunderbird on another computer, or OWA.  In
	particular, the header information appears missing and has been
	inserted in body of message.

- Viewing message source in Thunderbird reveals what seems to be the
	problem.  Some new lines have been inserted at the beginning of the
	header section, including an X-Offlineimap line, followed by a blank
	line.  Because of the blank line, the rest of the header is now
	interpreted as message body.

Is this a bug? If the blank line were removed, I think it would be fine.