Not only have I never ran across a hallucination in the past ~6 months or so; the latest Opus models have gotten to the point where they can emit inline assembly that is _superior_ to what gcc or clang can generate from optimized cpp. Had it rewrite a hot simd loop that took it from ~10 flops/cyc to ~14 by shaving off broadcasts. I _could not_ get any compiler to do this, no matter which flags I tried to use. So I literally have no idea what these people are talking about when they claim that SOA models hallucinate constantly.
Last week, Opus gave me a decrement instead of an increment, on one particular line. Where I already had the decrement, but it was changing the width of the datatype everywhere.
And it took "convincing" that it had made a mistake.