It is working for me (Brazil). Maybe some geographic cache?
:~> dig ns1.kissthenet.net
; <<>> DiG 9.11.2 <<>> ns1.kissthenet.net
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 11756
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 13, ADDITIONAL: 11
;; QUESTION SECTION:
;ns1.kissthenet.net. IN A
;; ANSWER SECTION:
ns1.kissthenet.net. 21492 IN A 159.148.147.201
;; AUTHORITY SECTION:
net. 72325 IN NS h.gtld-servers.net.
net. 72325 IN NS e.gtld-servers.net.
net. 72325 IN NS i.gtld-servers.net.
net. 72325 IN NS a.gtld-servers.net.
net. 72325 IN NS c.gtld-servers.net.
net. 72325 IN NS g.gtld-servers.net.
net. 72325 IN NS l.gtld-servers.net.
net. 72325 IN NS d.gtld-servers.net.
net. 72325 IN NS b.gtld-servers.net.
net. 72325 IN NS j.gtld-servers.net.
net. 72325 IN NS f.gtld-servers.net.
net. 72325 IN NS k.gtld-servers.net.
net. 72325 IN NS m.gtld-servers.net.
;; ADDITIONAL SECTION:
e.gtld-servers.net. 2568 IN A 192.12.94.30
i.gtld-servers.net. 15858 IN A 192.43.172.30
a.gtld-servers.net. 1311 IN A 192.5.6.30
c.gtld-servers.net. 141625 IN A 192.26.92.30
l.gtld-servers.net. 72325 IN A 192.41.162.30
d.gtld-servers.net. 141625 IN A 192.31.80.30
b.gtld-servers.net. 72325 IN A 192.33.14.30
j.gtld-servers.net. 72325 IN A 192.48.79.30
f.gtld-servers.net. 72325 IN A 192.35.51.30
k.gtld-servers.net. 72325 IN A 192.52.178.30
m.gtld-servers.net. 72325 IN A 192.55.83.30
;; Query time: 2 msec
;; SERVER: 10.10.2.1#53(10.10.2.1)
;; WHEN: Wed Jun 27 19:49:35 -03 2018
;; MSG SIZE rcvd: 449
:~> dig ns2.kissthenet.net
; <<>> DiG 9.11.2 <<>> ns2.kissthenet.net
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 58504
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 13, ADDITIONAL: 11
;; QUESTION SECTION:
;ns2.kissthenet.net. IN A
;; ANSWER SECTION:
ns2.kissthenet.net. 21432 IN A 159.148.172.251
;; AUTHORITY SECTION:
net. 72252 IN NS l.gtld-servers.net.
net. 72252 IN NS d.gtld-servers.net.
net. 72252 IN NS b.gtld-servers.net.
net. 72252 IN NS j.gtld-servers.net.
net. 72252 IN NS f.gtld-servers.net.
net. 72252 IN NS k.gtld-servers.net.
net. 72252 IN NS m.gtld-servers.net.
net. 72252 IN NS h.gtld-servers.net.
net. 72252 IN NS e.gtld-servers.net.
net. 72252 IN NS i.gtld-servers.net.
net. 72252 IN NS a.gtld-servers.net.
net. 72252 IN NS c.gtld-servers.net.
net. 72252 IN NS g.gtld-servers.net.
;; ADDITIONAL SECTION:
l.gtld-servers.net. 72252 IN A 192.41.162.30
d.gtld-servers.net. 141552 IN A 192.31.80.30
b.gtld-servers.net. 72252 IN A 192.33.14.30
j.gtld-servers.net. 72252 IN A 192.48.79.30
f.gtld-servers.net. 72252 IN A 192.35.51.30
k.gtld-servers.net. 72252 IN A 192.52.178.30
m.gtld-servers.net. 72252 IN A 192.55.83.30
e.gtld-servers.net. 2495 IN A 192.12.94.30
i.gtld-servers.net. 15785 IN A 192.43.172.30
a.gtld-servers.net. 1238 IN A 192.5.6.30
c.gtld-servers.net. 141552 IN A 192.26.92.30
;; Query time: 2 msec
;; SERVER: 10.10.2.1#53(10.10.2.1)
;; WHEN: Wed Jun 27 19:50:48 -03 2018
;; MSG SIZE rcvd: 449
Again, this is not cache or something like that geographical, this is a miss change after switching to new nameserver. They only have to change 2 glue record (20 secs operation on registrar provider).
To test, launch this dig query
dig ns mynetname.net @a.gtld-servers.net
And you will see the old ns1 and ns2 glue record.