DNS64 and BIND9 behavior

All,

How does the change from NODATA responses to NXDOMAIN in BIND9 impact DNS64 behavior? It was my understanding that (for example), if using DNS64 "Secondary" option that an AAAA request is first sent to the DNS server from the BIG-IP. And then only in the event of "NODATA" AAAA response does the BIG-IP send a A request to the DNS server. Since BIND9 seemed to have cut out "NODATA" responses for non-existing records (assuming that the domain exists) and instead returns just "NXDOMAIN, I'm wondering if BIP-IP DNS64 has changed to translate on NXDOMAIN responses instead of NODATA responses.

Thanks, Dave