FYI, the ('wrong') files downloaded by Firefox appear to be a few bytes longer in size, i.e.:
(wrong) aaaa.20110915.022723.pnd CRC32=C820F7CB Size=17,263,828
(right) aaaa.20110915.022723.pnd CRC32=E5CD3F0F Size=17,263,662
given more weight to this being a 'declared size' issue.