bind returns empty record first time

[Captain Dondo]

Sometimes, the first time sendmail asks for an MX record, it gets back 
an empty record, resulting in email getting bounced with a 'no data 
known' error, or it gets back a NXDOMAIN.

The second time around, everything works fine.

I've captured this in two files I've put on my website,
http://www.seiner.com/dns.prob and http://www.seiner.com/named.prob; the
first one is a capture of a dig and the second is the corresponding
debug output of bind running with -d 255.

Notice that the empty response comes from my ISP's name server, while 
the correct, second response comes from local cache....

I've googled all over the place, and I can find a few references to
various failures, but sendmail apparently addressed this type of failure 
a few versions ago....

I suspect it also happens with web surfing, since periodically I get a
'can't find xxxx.com' type of errors while browsing, but email is the 
big problem, as email is getting bounced all the time.

I've tried the recommended fix for similar problems of adding the 
timeout option to resolv.conf, but it hasen't made any difference....

[root at tooth html]# cat /etc/resolv.conf
domain seiner.lan
options timeout:1 attempts:6
nameserver 192.168.128.2
nameserver 66.178.167.27
nameserver 66.178.152.14
order hosts,bind

I would appreciate any advice on this....