People don't need LLMs to lie, and someone in the comments tells a similar experience. You can also find plenty of similar anecdotes using a search engine of your choice.
A lot of people use LLMs to clean up their sloppy text. Not realizing how fake it makes them sound. non-native speakers lacking confidence in their English are a type of llm abuser. It doesn't necessarily make the content fake.
This post is written by an LLM, and possibly a complete fabrication.