Just curious, how can you be confident this was a hack? I mean what is the probability that they've just had bad luck and never got a winning answer but have genuinely been playing fairly?
I've seen the evidence and am convinced (multiple different ways, even) that the miner in question was in fact block withholding.
Whether it was intentional or accidental, I consider irrelevant.
wizkid057 plans to release more information at some point publicly, I'm not sure when.