“carefully checked and corrected” is also the sort of thing that llm's like to insert when you tell them to carefully check and correct in the prompt, and isn't otherwise really a natural thing to write.

LLMs love all kinds of idioms that indicate quality work (even when it isn't): 'checked', 'correct/corrected', 'witnessed', 'works/working', 'verified', 'validated'. They overuse these to the point that they become flags rather than reassurances.