Duplicate Handshake records

[agaffney]

We're seeing duplicate A records for NS records on some domains.

$ dig -p 8053 @localhost blinklabs.

; <<>> DiG 9.18.39-0ubuntu0.24.04.2-Ubuntu <<>> -p 8053 @localhost blinklabs.
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 11217
;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 2, ADDITIONAL: 4
;; WARNING: recursion requested but not available

;; QUESTION SECTION:
;blinklabs.			IN	A

;; AUTHORITY SECTION:
blinklabs.		999	IN	NS	ns1.blinklabs.
blinklabs.		999	IN	NS	ns2.blinklabs.

;; ADDITIONAL SECTION:
ns1.blinklabs.		999	IN	A	44.231.6.183
ns1.blinklabs.		999	IN	A	44.231.6.183
ns2.blinklabs.		999	IN	A	54.214.136.246
ns2.blinklabs.		999	IN	A	54.214.136.246

We only get each A record once from the Handshake node.

$ dig ns blinklabs. @x.x.x.x -p 5349

; <<>> DiG 9.18.39-0ubuntu0.24.04.2-Ubuntu <<>> ns blinklabs. @x.x.x.x -p 5349
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 30725
;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 2, ADDITIONAL: 4
;; WARNING: recursion requested but not available

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;blinklabs.			IN	NS

;; AUTHORITY SECTION:
blinklabs.		21600	IN	NS	ns1.blinklabs.
blinklabs.		21600	IN	NS	ns2.blinklabs.

;; ADDITIONAL SECTION:
ns1.blinklabs.		21600	IN	A	44.231.6.183
ns2.blinklabs.		21600	IN	A	54.214.136.246