Weird mailman issue - adding -bounces to list's email address

[JerkyChew]

Hi,

A client of ours has a mailman list set up called [email protected]. For some reason, when anybody posts to this list, the return address of the list comes across as "[email protected] [mailto:[email protected]] On Behalf Of firstname lastname"

(User and domain specific details modified)

I've gone all through the admin panel, and I can't find any setting that would add a -bounces to the email address. Does anybody have any ideas?

Thanks.