Yeah, this is close to my experience with it as well. The AI spits out some tutorial code and it works, and you think all your problems are solved. Then in working with the thing you start hitting problems you would have figured out if you had built the thing from scratch, so you have to start pulling it apart. Then you start realizing some troubling decisions the AI made and you have to patch them, but to do so you have to understand the architecture of the thing, requiring a deep dive into how it works.

At the end of the day, you've spent just as much time gaining the knowledge, but one way was inductive (building it from scratch) while the other is deductive (letting the AI build it and then tearing it apart). Is one better than the other? I don't know. But I don't think one saves more time than the other. The only way to save time is to allow the thing to work without any understanding of what it does.