Secondary serving non-current data from cache?

[Jonathan de Boyne Pollard]

SF> Last night I updated some A records [...]
SF>                                 2003092905 ; serial
SF> [...]

Your post is dated 2003-10-01.  "Last night" is therefore 2003-09-30.  Why,
therefore, does the serial number in your "SOA" resource record read
"2003092905" ?