There seems to be more to it than that - in my experience with LLMs, they are good at finding some relevant facts but then quite often present a non-sequitur fo

There seems to be more to it than that - in my experience with LLMs, they are good at finding some relevant facts but then quite often present a non-sequitur for a conclusion, and the article's title alone indicates that the problem for LRMs is similar: a sudden fall-off in performance as the task gets more difficult. If the issue was just non-determinism, I would expect the errors to be more evenly distributed, though I suppose one could argue that the sensitivity to non-determinism increases non-linearly.