Comment 3 for bug 558240

I fixed this as suggested in the patch attached to comment #1. It should really be addressed in the send() method of the Message.UserNotification() class, except that it may not be possible to correctly decide there whether the appropriate value is auto-generated vs. auto-replied, thus it may require modifying all the callers anyway.

Invitations and (un)subscription confirmations have already been fixed per LP:265831.