this may be to do with it but it needs to bix fixed either way, clients who were using the web mail have lost all there old emails as the new web mail does not use the /mail dir in the /home/&user&/mail but it uses new folders/files in /home/&user&.
This has caused many customers to say they have lost there email and having to use the old web mail but since this morning the old web mail apps have gone :/
Actually, I think the answer to your problem here is that you have the &Move old msg to SAVED at logout:& box checked. Uncheck that and when you relog back in, the mail is still there.