[fetchmail] fetchmail re-polls repeatedly until mailbox is empty

Hi, some new behaviour seems to have been added between 5.9.0 and
6.2.0.  I've been through the Changelog, but can't identify what it
might be - I'd really like to turn this re-polling feature off.

I have an IMAP mailbox and am using fetchmail to retrieve all mail,
I'm not using daemon mode:

    poll mail.webarchitects.co.uk proto imap user bruno
    password ************** fetchall ssl is bruno here;

What is happening is that the mail is retrieved and flushed:

> [snip]
> fetchmail: IMAP< * 1 FETCH (BODY[TEXT] {802}
>  (802 body octets) **************************
> fetchmail: IMAP< )
> fetchmail: IMAP< A0087 OK FETCH completed.
> fetchmail: SMTP>. (EOM)
> fetchmail: SMTP< 250 Ok: queued as 5099E544
>  flushed
> fetchmail: IMAP> A0088 STORE 1 +FLAGS (\Seen \Deleted)
> fetchmail: IMAP< * 1 FETCH (FLAGS (\Seen \Deleted \Recent))
> fetchmail: IMAP< A0088 OK STORE completed.
> fetchmail: IMAP> A0089 EXPUNGE
> fetchmail: IMAP< * 1 EXPUNGE
> fetchmail: IMAP< * 2 EXISTS
> fetchmail: IMAP< * 2 RECENT
> fetchmail: IMAP< A0089 OK EXPUNGE completed
..then fetchmail checks to see if anything else has arrived since
and downloads that as well:

> fetchmail: selecting or re-polling default folder
> fetchmail: 2 messages waiting after re-poll
> 2 messages for bruno at mail.webarchitects.co.uk.
> fetchmail: IMAP> A0090 FETCH 1:2 RFC822.SIZE
> fetchmail: IMAP< * 1 FETCH (RFC822.SIZE 557)
> fetchmail: IMAP< * 2 FETCH (RFC822.SIZE 369)
> fetchmail: IMAP< A0090 OK FETCH completed.
> [snip]
Presumably it will keep on re-polling, hoping that eventually the
mailbox will be empty.  How can I get it to only download the
messages that are in the mailbox initially?

-- 
Bruno