On my desktop (with chrome) searching google via HTTPS I get search results that first redirect to a HTTP page on Google then does a client redirect to the search result. This produces referer information to the search result.

It seems this step is not being taken on iOS, it could be google who singling out iOS6 and not doing the redirect to the HTTP page.

Tried this on my Nexus 7 and didn't get the redirect so it may be something they're doing for mobile user agents. Its definitely not specific to iOS6

Probably to reduce latency. Another hop is expensive on mobile networks.

That's interesting. But as a counter point, my blog gets a bunch of hits from Google marked as "[Secure Search]", so I guess they don't always do it.