This is my experience too. Also, their propensity to jump into code without necessarily understanding the requirement is annoying to say the least. As the project complexity grows, you find yourself writing longer and longer instructions just to guardrail.

Another rather interesting thing is that they tend to gravitate towards sweep the errors under the rug kind of coding which is disastrous. e.g. "return X if we don't find the value so downstream doesn't crash". These are the kind of errors no human, even a beginner on their first day learning to code, wouldn't make and are extremely annoying to debug.

Tl;dr: LLMs' tendency to treat every single thing you give it as a demo homework project