Problems with headers

["troop899" <sm @ troop899 . org>]

I have mysterious things happening in my majordomo-generated mail headers,
like this:

X-Authentication-Warning:santeelodge.org: santeelodge set sender to
owner-santee@1 using -f

The owner-santee@1 thing is obviously wrong...  And this:

Sender:owner-santee@1

How do I fix this, should I bother, and could this be causing ISPs like AOL
to automatically trash my majordomo mail?

Thanks!

Mark