Atomic Shrimp has an aside in a recent video about how to identify AI writing. It's worth a look https://youtu.be/VeD9dUUFl-E?t=668

He's not the only one to point out these things that LLMs (currently) tend to output, but this is one of the shorter overviews of the tells you can spot.

E.g. the not x but why slop leader board