glue record problem

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dear all :
   if I has following RRs in xxx. domain in same zone file
   aaa          IN     NS     ns1.aaa
   ns1.aaa    IN    A        10.10.10.1
   bbb.aaa    IN    A        10.10.10.2

and in "ns1.aaa.xxx." name server

then I use nslookup to query "bbb.aaa.xxx." domaint name,
(1) server point to the name server that authorize "xxx." domain
(2) server point to other name server that not authorize this domain
but I all receive repsponse with "non authorized answer with bbb.aaa IN A
10.10.10.2"
,why I can not  receive repsponse with "can't find bbb.aaa.xxx: Non-existent
host/domain",thank you.

Best Regards,
Eric