Interestingly, I can seen to reproduce this with consistency at work across both Firefox and Chrome-based browsers.
We do have web filters to some extent (standard firewall that throws up a page if you search for certain content) but historically this hasn't been an issue.
Curiously, I can't see any network requests being killed or eaten, they just... seem to stop. The client receives the usual sets of lng/lat coordinates from Apple Maps + the Wikipedia layer but then just hits the NaN lng/lat error.
For what it's worth, I confirmed this both via the Network Requests tab as well as using https://proxyman.io to capture traffic coming from my browser.
As far as I can tell, all of the required endpoints are all returning valid coordinates as well.
I'm happy to send through a HAR file if that's useful although I won't post it publically of course because it'll have my session token inside it.
I did also wonder if it was perhaps something to do with diacritics but searched for other areas like Whangārei work fine.