Run it up the chain

They're either lying about using AI, or they're incompetent enough to produce AI quality (read: Garbage) code, either way the company should let them go

That would be the nuclear option, but if you have any rapport at all with the person or team in question, you could also just pull them aside, ask if they are under unusual pressure to show progress, and make it clear that you get it, and you want to help, but that you can't if you're drowning in AI slop code review. I imagine it's a junior doing this, in which case it's in their career interest to stop and start acting like a professional. I've had seniors tell me more or less the same thing, in the pre-llm era: "slow down and get it right." Sometimes you just need to hear that.