Different variants of the same package on ftp.FreeBSD.org

[Lena at lena.kiev.ua]

Hi,

~ $ host ftp.freebsd.org
ftp.freebsd.org has address 204.152.184.73
ftp.freebsd.org has address 62.243.72.50
ftp.freebsd.org has IPv6 address 2001:6c8:6:4::7
ftp.freebsd.org has IPv6 address 2001:4f8:0:2::e
~ $ echo -e "dir mathopd*\nquit" | ftp ftp://204.152.184.73/pub/FreeBSD/ports/i386/packages-6-stable/All/
Connected to 204.152.184.73.
220 Welcome to freebsd.isc.org.
...
-rw-r--r--    1 110      1002        56584 Jan 24 06:20 mathopd-1.5p6.tbz
~ $ echo -e "dir mathopd*\nquit" | ftp ftp://62.243.72.50/pub/FreeBSD/ports/i386/packages-6-stable/All/
Connected to 62.243.72.50.
220 ftp.FreeBSD.org NcFTPd Server (licensed copy) ready.
...
-rw-r--r--   1 ftpuser  ftpusers     56520 Nov  4 14:48 mathopd-1.5p6.tbz

Different sizes, different dates. The November variant is broken
(installed package crashes at first connection), the January variant works.
I.e. half of users get the broken variant from ftp.FreeBSD.org.
Local mirrors contain the broken variant.
http://www.freshports.org/www/mathopd  lists last commit on August 13, 2007.
How, why different variants?