NS records for subzone cause BIND 9 failures

[Kurt Boyack]

When a parent zone has subzone data in it, NS records for the subzone
will cause BIND 9 servers to fail to resolve any of the subzone's
data. The problem does not exist with 8.2.3, but does with 9.2.1 and
9.3.0.

I have a feeling that the reason for this is that BIND 9 is stricter,
but have not been able to find any documentation that says if NS
records should or should not be present in this case.

The zones in question are internal and the NS records are coming from
Microsoft servers.