syncing two existing mailboxes

["Shankar Gopalakrishnan" <shankargopal@xxxxxxxxxxxxxx>]

Dear all,

I am having some difficulties with offlineimap 6.0.3.  I have an
existing dovecot mailstore on my local computer which corresponds to
three IMAP accounts (two Gmail and one Fastmail).  Using a different
distro/system, I was earlier syncing these accounts from the remote
servers with my local dovecot system using offlineimap 5.99.  That was
working great.  Now I've started with a new version of the distro, set
up dovecot to access the same mail store (which appears to be running
fine).  I would assume offlineimap would sync the mailboxes and not
download messages again.  However, when I run offlineimap, it starts
downloading what looks like all the messages in all the mailboxes.  When
I look at the mailstore using a client, the messages are clearly getting
duplicated.  

Any idea what's going on?  Is this the expected behaviour?  

Thanks very much in advance
Shankar Gopalakrishnan