AI produces code that often looks really good, at a pace quicker than you can read it.
It can be really, really hard to tell when what it's producing is a bag of ** and it's leading you down the garden path. I've been a dev for 20 years (which isn't to imply I'm any good at it yet) and it's not uncommon I'll find myself leaning on the AI a bit too hard and then you realise you've lost a day to a pattern that wasn't right, or an API it hallucinated, in the first place.
It basically feels like I'm being gaslit constantly, even though I've changed my tools to some that feel like they work better with AIs. I expect it's difficult for junior devs to cope with that and keep up with senior devs, who normally would have offloaded tasks to them instead of AI.