Yes, scientific articles are expensive.
Doesn’t have to be scientific articles, it can easily be a normal article that state that scientists have confirmed the findings independently.
This is a very common thing for normal media to describe. The second article you linked would most probably have included that if such confirmation existed.
I linked to evidence that mathematicians are using LLMs to find proofs
No you didn’t, the article described a researcher testing the capabilities of AI, nothing in the article was really about math, it was all about the AI, and the whole story reeks of sensationalism.