Tethered my laptop to a phone with Vodafone SIM card and noticed this.
Got this error on Test your IPv6. though:
Danger! IPv6 sorta works - however, large packets appear to fail, giving the appearance of a broken website. If a publisher publishes to IPv6, you will believe their web site to be broken. Ask your ISP about MTU issues; possibly with your tunnel. Check your firewall to make sure that ICMPv6 messages are allowed (in particular, Type 2 or Packet Too Big)