[fetchmail]idfile UIDLs being cleared

I use Fetchmail to retrieve mail from several POP3 hosts.  For
some hosts, I use "keep", "no flush", and "uidl" to allow mail to
stay on the servers so that I can retrieve it later from home or
work.

When Fetchmail is run like this:

        $ fetchmail servername.tld

it gets the relevant data from the ~/.fetchmailrc file and
fetches the mail appropriately.  However, if it retrieves mail,
it seems to lose all UIDLs associated with other hosts.  This
results in some messages from the other hosts being downloaded
again if I fetch mail.

If I fetch mail from all accounts in one process by:

        $ fetchmail

it keeps all the UIDLs from all the hosts together in one file.
The problem arises only if I specify a single host on the command
line.

Am I missing something obvious to prevent this problem?  I would
think it would be best if Fetchmail didn't obliterate the UIDLs
associated with other hosts if it is not retrieving mail from
those hosts.

Thanks,

        -- Mr. Wade

-- 
Linux: The Choice of the GNU Generation