Unfortunately this is due to a Gmail policy which is found here:  http://support.google.com/mail/bin/answer.py?hl=en&answer=6588 .  


Not receiving email from groups


When you send mail to any group or mailing list you subscribe to, Gmail automatically skips your inbox and archives the message to save you time and prevent clutter. The message will appear in your inbox if someone responds to it or if there is an error delivering the message. If you'd like to view your message, you can find it in Sent Mail or All Mail.


There does not seem to be any willingness on Gmail's part to change this policy.  The only workaround for Gmail users is to receive an acknowledgement that their mail was posted, by setting their personal subscription options to ACK NOREPRO.