I feel I should throw my 2 cents in here: I don't doubt that at least some of the arena decks starting with 1hp are awesome decks that have decayed drastically, and are still there because they haven't lost enough times yet compared to their wins. However, I have also had normal opposing arena decks get a max hp of 1 mid way through matches, on multiple occasions.
It seems to happen as I finish turns, because I only see the change in the health bar for a fraction of a second before insta winning (though there was one instance where it may have happened in between me playing a card and pressing end-turn, I’m not sure). I haven’t noticed any unusual payouts. Indeed, last time it annoyingly did it after I’d carefully frozen some of my own creatures to ensure an elemental mastery through healing shards, only to have the opponent die at the first hit and give me half the intended payout :/ .
I may have to start hovering my finger over print screen when I end turns to try and catch it in the act.
