Yesterday I reported an issue to my registrar about DNSSEC records not deleting (I did a key rollover) and also being deleted when Whois information is updated. The response this morning was they have identified an issue at the registry and are working through it with NZRS. I don't have any more details but for obvious reasons I recommend anyone using DNSSEC to check the updates in the Whois until this has been solved, lest your domain become unavailable.