To summarize, a lot has been discussed recently about whether LLMs are just really, really good at finding connections between existing information (i.e. the world's smartest and best search engine), or whether they are capable of discovering truly unique, novel ideas. Because many of the very impressive recent AI math results were often just tying together ideas and theories that were already known (and I don't mean to minimize those accomplishments), it was surmised (and, just speaking for myself, hoped) that LLMs operated within this "convex hull", and thus there would always be at least some axis where LLM-based AI wouldn't surpass humans.
Now, this idea of the convex hull of training data is not very clearly defined, and people can and have argued about what it means. But in this case, OpenAI disproved a conjecture that was widely assumed to be true. This was a genuinely surprising result that many experts were shocked by. I'm not a mathematician so I'm not qualified to determine if this was a "truly unique" realization, but a really surprising result seems like it would be a candidate for AI solving a problem in a manner "outside the convex hull".