LLMs will do things no human developer will ever do. There are unspoken default assumptions a human will not violate that an LLM will.

I do a lot of LLM coding and I catch about one of these per week. But I still look at the code after the LLM writes and reviews it. So I'm going slower than most on here, so my default assumption would be theirs are doing this more often that once/week. Whether or not it matters depends upon your project.

My favorite one from the last month was the LLM designed monster hit points in a way that everyone is healed to full between combat. No, it was not intentional, HP were just stored in a way that the structure storing it completely disappeared outside actual combat.