Sounds like an air pocket event from the description; hitting a pocket of different temperature air that has a different viscosity to the surrounding environment. It's still summertime in the southern hemisphere so pockets of warm air in an otherwise cool cruising altitude might be involved. An hour away from Auckland could mean they were on a descent path as well, which implies dropping through different layers of the atmosphere, too.
Sounds like shitty turbulence; let's see what the investigation reveals.
> “I used to be a flight attendant and this is the first time I’ve ever ... the whole plane just froze,” she said.
Note: I edited the title to keep in under the character limit and to give context relevant to recent discussions.
Additional news sources:
- https://www.stuff.co.nz/nz-news/350209071/sydney-auckland-fl...
- https://www.nzherald.co.nz/nz/large-emergency-response-at-au...
- https://www.rnz.co.nz/news/national/511423/24-people-treated...