one of a Google Group with higest activity on yesterday whoever sends mail to that groups gets a failure notice kinda like this

   From: Mail Delivery Subsystem <MAILER-DAE...bos-mail-zmail2.lycosmail.com>
Date: Sat Jul 15 05:36:06 EDT 2006
Subject: Returned mail: see transcript for details
To: m...sankaranand.com

The original message was received at ...

   ---- The following addresses had permanent fatal errors ----
<jobsdu...lycos.com>
   (550 <jobsdu...lycos.com>: No thank you rejected: Account Unavailable:
Possible Forgery)

But the message reaches google group and also a error message is delivered to the users who sends mail.

So the admin changed the group email and it worked well and again at the same time today the same error occured and its still occuring that whoever sends mail to the group gets a error message.

Do you think there is an Exploit of Spam or is that a newly Discovered Bug in Google Group which is in Beta .........