I agree. The idea that mathematical achievements by LLMs could involve plagiarism didn't seem common before but now the question can be asked of any new novel proof of construction generated by LLMs.

It's also notable that the Open AI proof may not even be interesting to mathematicians.

Even if people already had an idea that LLMs were training on user inputs, it's the first time it's actually caused an issue. Mathematicians, and plenty of researchers, working in ambitious or competitive field now have a very good reason to avoid LLMs.