Bug in bind? MX and no A record

[kernel at pkts.ca]

Hi..

I've been debugging an email problem.  A domain (example.com) has an
MX record but no A record.

# killall named
# named
# dig example.com mx
  * this works
# dig example.com
  * this says 'NXDOMAIN'
# dig example.com mx
  * now this says 'NXDOMAIN', but it worked 2 seconds ago!?

The MX record won't come back until named is restarted.  It might come
back after the negative caching timeout, but I'm Not That Patient(tm).

This is with BIND 9.2.2 and also today's BIND, 9.3.0rc2.

Reproducible?  Real bug?  Design feature?  Let me know.

Thanks!
--
Penelope Fudd