I'm only an "expert" in computer science and software engineering, and can say that - neither of widely available LLMs can produce answers at the level of first year CS student; - students using LLMs can easily be distingished by being wrong in all the ways a human would otherwise never be.
So to me it's not really the question of whether CS-related benchmarks are false, it's a question of how exactly did this BS even fly.
Obviously in other disciplines LLMs show similar lack of performance, but I can't call myself an "expert" there, and someone might argue I tend to use wrong prompts.
Until we see a website where we can put an intermediate problem and get a working solution, "benchmarks show that our AI solves problems on gold medalist level" will still be an obvious BS.