Clearly, Fable 5 didn't even have the decency to wait until the next model refresh cycle to show up. It was already sitting there waiting.
Either the capability gains in bigger, badder models are actually unrelated to "gotchas" being discovered, or LLMs are already acquiring Skynet levels of disrespect for cause and effect.
Which I suspect is what happened here, given the trail of smaller / local models that successfully answer the question, too.
That said, "curse of reversability" is real, as much for LLMs as it is for people.