Not in my experience. They just regurgitate code, and juniors don’t know if/why it’s good or bad and consequently can’t field questions on their PR.
“It’s what the LLM said.” - Great. Now go learn it and do it again yourself.
I always say "own the output". No need to do it by hand but you better damn well research _why_ the AI chose a solution, and what alternatives there are and why not something else, how it works and so on. Ask the AI, ask a seperate agent/model, Google for it, I don't care, but "I don't know the LLM told me" is not acceptable.
For me, the hardest part of software development was learning incantations. These are not interesting, they're conventions that you have to learn to get stuff to work. AI makes this process easier.
If people use AI to generate code they don't understand, that will bite them. But it's an incredibly tool for explaining code and teaching you boring, rote incantations.
This just means you have bad juniors who aren’t interested in learning.
Unless your company is investing in actually teaching your junior devs, this isn't really all that different than the days when jr devs just copied and pasted something out of stack overflow, or blindly copied entire class files around just to change 1 line in what could otherwise have been a shared method. And if your company is actually investing time and resources into teaching your junior devs, then whether they're copying and pasting from stack overflow, from another file in the project or from AI doesn't really matter.
In my experience it is the very rare junior dev that can learn what's good or bad about a given design on their own. Either they needed to be paired with a sr dev to look at things and explain why they might not want to something a given way, or they needed to wind up having to fix the mess they made when their code breaks something. AI doesn't change that.