I would guess it's the 'vast' and the 'unprecedented' for example.

The cause of anomalous (>40 K) high superconducting transition temperatures in mixed copper (III) oxides is one of the most, if not the most, intensively studied questions in condensed-matter physics. If the researchers believe their experimental system can answer those questions, "vast" and "unprecedented" would be appropriate.

Maybe just a combination of academic jargon and English not being the authors first language? At this point I would also not be surprised if language models are used for writing abstracts.

This is Nature. If they stopped doing editorial work regarding writing style, and use LLMs to generate abstracts, it seems they have outlived their usefulness.

New here?