This has happened to me a total of 3 times since i started playing at launch.
There was once where i figured it was a bug or disconnect issue due to the circumstances of the game.
Curiously, the other two times were somewhat similar in nature.
The first was a blatant cheater in arena. I had lethal Within two turns, after holding out against a mage who had the better opener and fighting back(couple years ago when mage was arena standard). The mage had no board and a couple cards in hand. He had been quiet all game. His turn starts, he emotes thank you twice and hovers his card, then proceeded to do some other interaction while the card appeared to hover.
I was then stuck with this punk who emoted thank you and well played over and over, hovering that fn card. i knew what happened, and was so pissed bc it was in arena, that i remembered every little detail i just posted.
The third time i encountered this cheat was just now, playing on mobile. Things have been fine all day, and connected to a game with an aggro hunter that was going his way until i turned it around on him. what do you know, the second ive built a powerful mech boardof taunts and stealths after his little weenie dogs had run out, he card hovers. i am wary, but see him flicking thru his cards and selecting another. i figure its just a visual bug. He pulls off a flanking shot (i see the card get played and the animation but my minion doesnt die and his woof doesnt appear - but the sound is made). After about 3 minutes, i know whats happened. He emotes well played, and i shut the game off.
Blizzard and their knights will gaslight anyone who brings up these “bugs”, and im sure one, if not 2(the hunter i just played and a druid card hover way back) have been actual disconnects. But att least one of my experiences was a cheater. Blizzard acknowleges there are programs that can exploit the game and do this then in the same post will tell someone they were definitively experiencing disconnect. its less work for them to blame connection gremlins than to hunt down and ban those using this software and to reimburse those who waste money on arenas compromised by these people.
so if its random, tell me why it never happens in my favor or at times other than when im about to win?