I also assume mis ids considering no comments, the Tiritiri Matangi birds I also believe are just erronous ids by tourists, with although some observations having photos I find it more likely to be people forgetting where they were as theres absolutely no mention of the birds online.
Not the case with the Tiri birds, paradoxdinokipi. There was a bird on the Island for 18 years, disappearing 15-20 years ago. The story went that it was likely dumped there in the '80s. I heard this bird calling on many occasions, usually at night, and saw it once in Wattle Valley. Then, some time around 10 years ago, a visitor reported seeing one on the Island, and had a video to prove it. I don't know what happened to this individual (the bird, not the visitor), but it was never seen again