Some people believe that MailingLists should not add Reply-To: headers to Email posted through the list, a practice known as ReplyToMunging, on the grounds that distinguishing whom a reply should be addressed to is really the recipient's MailClient's job. There is a constant ReligiousWar with people who prefer ReplyToMunging.
See:
lib/main.php:944: Notice: PageInfo: Cannot find action page
"Reply-To"