Usermin Read Mail does not sync read flags with IMAP in Maildir

How does Usermin's Read Mail module track read messages when operating in Maildir mode? It seems to be doing it in a manner such that mail messages read via IMAP (Dovecot) do not show up as read in Usermin, and mail messages marked read in Usermin do not translate to IMAP.

I thought there was a standard for this?