I've never seen that from an LLM; usually the error they make is I've asked them for too many things (a quantity which varies wildly), I get a response for about 3 of those things and a note saying something to the effect of "put more here".

A very common piece of advice is to include keywords in your resume in exactly the way they are typed in the advertisement. This is because of places that use ATS systems to filter down the "best" candidates based on how closely their skill set matches the requirements. For example, if the requirement says "Must have proficiency in the Python scientific computing ecosystem, including TensorFlow and Scikit-Learn," if you subscribe to the keyword methodology, you'd make sure to sprinkle in the exact phrase "Python scientific computing ecosystem" on the off chance that some non-domain-expert in HR copied and pasted into their ATS.

I can see how someone would take that advice and include exact phrases in their cover letter in an attempt to get through the filters.