I think that there is a general consensus that the the exploitation of the Twintania bug was deliberate and technically against the rules, it is difficult to argue otherwise.
However, I am not without sympathy. Like many others, the lead group in my FC has been banging their heads against the wall on that fight for a couple weeks now. Were I in a position where I had been faced with this bug after hours of attempts, I am unsure how I would have reacted. I am not particularly outraged that the decision was made to finish the encounter in the heat of the moment after who knows how many attempts, I might have done the same. I see it as an understandable and forgivable mistake. Some responses from the community have been unnecessarily harsh. They have been upfront about their kill being illegitimate, so in no way do I see this tarnishing the reputation of the first to finish Turn 5 without taking advantage of a bug.