I couldn't find the code that does this in my cursory check of the Android source code, but I think it's a misconfiguration check that's failing. That's the feeling I get from others reporting similar issues on help forums, anyway.
I think Android sees a world routable IP address, notices it has connectivity and then finds out the DNS server doesn't return IPv6 addresses for known IPv6 capable hosts (such as Google.com). That seems like a fair way to detect misconfiguration to me, though I would've put up a notification warning about the switchover so users can get someone to fix their issue.
I think Android sees a world routable IP address, notices it has connectivity and then finds out the DNS server doesn't return IPv6 addresses for known IPv6 capable hosts (such as Google.com). That seems like a fair way to detect misconfiguration to me, though I would've put up a notification warning about the switchover so users can get someone to fix their issue.