this bug happened when my opponent played anduin, the whole game froze for us, the hero power did not change and his hp where missing, no one could use cards anymore, it happend right after the transformation.
for further information: I quoted “oops” at the exact same moment.
I experienced the same issue.
Opponent played Anduin, no HP displayed, and game was stuck there.
I could see my opponent trying to play cards (e.g. the arrow when he targets an enemy) but no action was possible.
I ended up quitting the game.
This is happening to me for priest Galakrond. No health, game freezes. He’s trying to play cards too, turn won’t end.
Thanks for sharing a video, but please do not make it Private, we cannot see it. I would consider putting it as Unlisted instead, so that it won’t show up in normal YouTube feeds, but others can still see it.
video should be visible now. 
What this looks like is that you disconnected. While disconnected from the game server, you may still see emotes, card hover and arrow targeting from the opponent, since those are from direct connections between you and the opponent, not through the server. More info here:
Based on the sequence of events, looks like your opponent was continuing to attack you, played cards, etc. When you realize something like this happens, you can quit (Alt+F4 in Windows) and restart the game right away to reconnect to the game in progress. Hopefully you do it fast enough that you have not lost your next turn while reconnecting.