I tuned over to 7425 around 1230 Z to find RNZI was SIO 455, which is unusual but not unknown when it's supposed to be beamed toward Papua New Guinea. At 1257 they announced that they would change to 5980, but the bird chirp interval never ceased, and the transmission remained on 7425, still with a terrific signal. That makes it likely that the beam failed to switch to a northwesterly direction at 1100, indicating some kind of trouble with the switching service (likely an automatic, unmanned process) at Rangitaiki.