Technical debt due to accumulated excessively verbose, badly architected, often redundant, feature-bloated code which always looks good, even upon earnest review, but actually sucks and becomes extremely difficult to maintain in ways which are not obvious in code review. The issue is this: your tooling can help, and can make you feel better, and you might think you wrote all the prompts and made all the tools to mitigate these issues, but you haven't. If you're not consistently seeing it generate code that is very very close to the way a skilled senior dev such as yourself would have done it (with similar line count, etc), that is a red flag even if the code looks great and works.