Secondary serving non-current data from cache?

[Steve Francis]

Last night I updated some A records on the master for a zone. Watching
the log files on both master and secondaries, I saw the notifies go
out, and then the zone  transfers succeed.

THe issue is that the secondaries, while they had a current copy of
the zone file with the new IP addresses on disk (I could cat the file
and see the new data), were still serving the old IP data from their
cache. This seemed to continue for up to the length of the refresh
period of the SOA in the zone.

That  doesn;t seem correct - what's the point of the notify if its
still going to serve old cached data for the refresh period?

Or am I misinterpreting (or misconfiguring) something?
This is using bind9-9.2.2.

The SOA:
expertcity.com          IN SOA  expertcity.com. root.expertcity.com. (
                                2003092905 ; serial
                                3600       ; refresh (1 hour)
                                360        ; retry (6 minutes)
                                604800     ; expire (1 week)
                                600        ; minimum (10 minutes)
                                )

And the relevant part of the named.conf on the secondary:
match-clients { any; };
        recursion no;
        additional-from-cache no;

zone "expertcity.com" in {
        type slave; file "/slave/expertcity.com";
        masters { 64.74.80.9 ; } ;
};