Wasn’t that when he was playing a deck with a specific combo that would cause his opponent’s game to crash? Deliberately? Multiple times? On stream, where the fact that he was doing it intentionally was broadcasted to the world? I think he crossed the “don’t do anything an average player couldn’t do” line by doing it more than once.
Plus that bug was way more severe than this one. A Whizbang deck with a couple Hall of Fame cards isn’t a huge advantage since Whizbang decks aren’t exactly top tier. A two card combo that knocks opponents out of the game immediately is absolutely busted by comparison.
Here’s the thread where they’ve said they’ve fixed this already:
You can play him right now. If you find any more Hall of Fame cards, feel free to report them. Nobody else seems to be saying anything about them though, so you should be good.