Hi Micke,
I see the same messages here and suspect this to be a problem of the sending e-mail client.
For example, I can reproduce this with Netscape's 6.x or Mozilla's mail client but it's not doing it when sending from Outlook Express (not that I encourage to use that client due to it's security problems).
Most important, although the message looks a bit odd there should be no problem with the further delivery.
Regards,
Michael