Return Path is being rewritten

[Matthew Wolfe]

Hi,

I am not sure if this is a MailScanner or Sendmail thing but hopefully you guys 
can point me in the right direction.

I have a client who just got a new email address and when he sends email to me the
return path is rewritten to user at webhostingcompany instead of user at domainname. To
make things more interesting his webhosting provider and email provider are different
companies. If I send email to a email address that is not being scanned by MailScanner
the return address is correct. We scan about 30000 emails a day and I have never
seen anything like this. Any suggestions?

Thanks

Matt

P.S. Sorry if this is a repost, I didn't see it come through the first time.