How do I stop repeaed posts to a moderated public folder?

[-pete]

I am repeatedly receiving the same post to a folder I am moderator for. The
post author is not actively reposting the same message. The post author is
also repeatedly receiving the automated standard response message for each
occurrence.

We need to stop this repeated posting so both I (moderator) and the post
author aren't spammed by the public folder.

This is occurring for just one specific author. For everyone else, the
moderated public folder works as expected.

Thank you.