a death loop with DNS query

[Feng He]

When I dig this:

dig s1.mytest.blogchina.org +trace

I got many these info:

mytest.blogchina.org.   600     IN      NS      ns1.dnsv5.com.
mytest.blogchina.org.   600     IN      NS      ns2.dnsv5.com.
;; BAD (HORIZONTAL) REFERRAL
;; Received 95 bytes from 183.60.59.217#53(ns1.dnsv5.com) in 6 ms

mytest.blogchina.org.   600     IN      NS      ns1.dnsv5.com.
mytest.blogchina.org.   600     IN      NS      ns2.dnsv5.com.
;; BAD (HORIZONTAL) REFERRAL
;; Received 95 bytes from 112.90.143.36#53(ns1.dnsv5.com) in 116 ms

mytest.blogchina.org.   600     IN      NS      ns2.dnsv5.com.
mytest.blogchina.org.   600     IN      NS      ns1.dnsv5.com.
;; BAD (HORIZONTAL) REFERRAL
;; Received 95 bytes from 180.153.162.153#53(ns2.dnsv5.com) in 27 ms

mytest.blogchina.org.   600     IN      NS      ns2.dnsv5.com.
mytest.blogchina.org.   600     IN      NS      ns1.dnsv5.com.
;; BAD (HORIZONTAL) REFERRAL
;; Received 95 bytes from 221.130.12.61#53(ns2.dnsv5.com) in 165 ms

mytest.blogchina.org.   600     IN      NS      ns2.dnsv5.com.
mytest.blogchina.org.   600     IN      NS      ns1.dnsv5.com.
;; BAD (HORIZONTAL) REFERRAL
;; Received 95 bytes from 122.225.217.194#53(ns2.dnsv5.com) in 24 ms

mytest.blogchina.org.   600     IN      NS      ns1.dnsv5.com.
mytest.blogchina.org.   600     IN      NS      ns2.dnsv5.com.



What does this death loop mean? How it happened?

Thanks.