servfail's with 951b1

[grarpamp]

Hi. I upgraded from 941p1 to 951b1. Now I get servfail's on simple
dig's of random domains such as the one below and can't figure out
why. If I kill the server and restart, some other domain might go
servfail. I've attached two traces, the same query with a restart
in between: one good, one servfail. I diffed the two but it wasn't
clear to me what was up. So I guess I could use your eyes. Note my
config is /dev/null, this should result in a simple recursive caching
server and is easily replicable. Platform: FreeBSD RELENG_4 as of
the last commit. Other than the bind version, nothing else has
changed. Thanks.
/usr/local/bind951b1/sbin/named -c /dev/null -f -d 99

; <<>> DiG 9.5.1b1 <<>> @192.168.0.40 freebsd.org. a
; (1 server found)
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 19277
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;freebsd.org.                   IN      A

;; Query time: 4 msec
;; SERVER: 192.168.0.40#53(192.168.0.40)
;; WHEN: Tue Aug  5 01:50:43 2008
;; MSG SIZE  rcvd: 29