Are you sure it was not just a glitsch?

    $ dig a www.lancaster.ac.uk @1.1.1.1 +short
    www.lancs.ac.uk.
    148.88.65.80
    $ dig aaaa www.lancaster.ac.uk @1.1.1.1 +short
    www.lancs.ac.uk.
    2001:630:80:2ff::80:1