I have header retetion set for 2 days. I have header per server set to all. the rest is set to delete.
Tracking expired/purged headers is set to 6 days.
purge, delete, mark as deleted, read, flagged all checked.
Retention - let all incomming headers through checked.
everytime a rescan occurs I get header back that I've marked as read. They show back up as unread and new.