Private \seen flags lost during message move for other users

Hello,

I have a shared mailbox set up with a private index: maildir:/var/mail/public:INDEXPVT=~/Maildir/public

Per user \Seen flags are working fine until one user moves a message into another folder/sub-mailbox. For that user doing the move the message remains \Seen however for other users who have already seen the message the flag is lost and it appears unread in the new location. If the message is moved back it still appears unread to the other user even if had been read in that folder/sub-mailbox in the past.

Is there anyway to retain per user \Seen that follows the message when its moved?

Thank you. ​