GSLB via DNS local still resolve ip address unavailable ( member down)

Dear all

I have a GSLB system with wide IP list: hunght11.nislab.tech

and pool GSLB member: TTL=600 . Load Balancing Method: Round Robin

i have try test

1. From client nslookup to listener F5 GSLB, when a member down ex: wiki 2 down >> I only receive reply IP address for wiki 1 .100 >> OK (Correct)
2. But when I nslookup via LDNS ( on LDNS config Delegation DNS to F5 for hunght11.nislab.tech) then wifi 2 .102 down ( disable) I sitll recive ip wiki2 .102 when nslookup domain hunght11.nislab.tech >> Not correct >> down service

Do you know solution to it ?

Thanks

Hoang Hung