The downloads page links to https://channels.nixos.org/nixos-22.05/latest-nixos-minimal-x86_64-linux.iso. When I visit that link in Firefox (from a US east coast IP address), it has me download “nixos-minimal-22.05.615.11e805f9935-x86_64-linux.iso”. When I visit that link in the Tor Browser (from a Dutch exit node, at least at the moment), it has me download “nixos-minimal-22.05.2889.67e45078141-x86_64-linux.iso”.
I know that there’s always going to be some delay between the source of truth being updated and any caches being updated, but Hydra says that the 22.05.615 ISO was generated three months ago. Another ISO image, 22.05.693, was generated on the same day that the 615 one was. I would think that the 693 image or something newer would have made it into the cache at this point.
The latest ISO URL should use a 302 response code to indicate that the redirect destination might change in the future. Users who clicked the link before the response code is changed will still get the old ISO, but that might not be worth fixing. If someone really cares, they can just clear their browser’s cache.