Unfortunately the proof found by the LLM combines work by different teams of mathematicians that cannot individually be published as proofs. It's the equivalent of a scoop in investigation journalism by someone who was spying on journalists instead of doing any investigating. It's on lemmy/wired: https://lemmy.world/post/52843754
It's good that some do cite sources, however one major problem with generative AI is that it can produce volumes of output much faster than they can be verified. "You can always cross-check" is not viable at scale, and by the time LLM output gets cited, it becomes a quagmire potentially unlimited levels deep.
LLM output should never be treated as original until they can show their work transparently.