We have some cPanel servers with apache/Bind/CSF, I'm using the server in hetzner datacenter and they get me just one IP on a server so I'm using two DNS records by same IP like : ns1.serverone.com and ns2.serverone.com.
I used a domain name for handling the server name (like: hostname.serverone.com) and there is an active site with full of content account on the (serverone.com). But suddenly it stops working with "Domain lookup failure" on host tracker and "ERROR: One or more of your nameservers did not respond" on intoDNS, site dissappears, and when I terminate the site and restore today's backup the site comes back. BTW I am able to ping (hostname.serverone.com),(ns1.serverone.com), (ns2.serverone.com), but (serverone.com) is not accessible. All other domains are working smoothly with (ns1.serverone.com), (ns2.serverone.com). The serverone.com DNS is set for it's NS (ns1.serverone...). I had not any problem with this settings before.
I do not need to wait for propagation, because on one of servers there is a same domain that is without any content and unused , it's about many months it doesn't work.