someone posted this on /r/MachineLearning and I had the same experience and conclusion:

    I was having problems with Claude doing the same thing, even before Fable.

    The problems I had only happened in relation to AI research. It's not even only when training models, anything to do with analysis of local models or setting up test platforms for local models, and Claude would keep doing wrong things, would sabotage testing, would falsify reports, and would consistently suggest simply accepting trash results without looking into it and moving on to something else.
    Almost every response included a prompt to move on.

    So, I don't believe them when they say they won't silently sabotage, they already were doing it before they admitted it, and now they have admitted that they have the means, motivation, and intent.