When he was first hired, I asked him to refactor a core part of the system to improve code quality (get rid of previous LLM slop). He submitted a 2000+ line PR within a day or so. He's getting frustrated because I haven't reviewed it and he has other 2000+ line PRs waiting on review. I asked him some questions about how this part of the system was invoked and how it returned data to the rest of the system, and he couldn't answer. At that point I tried to explain why I am reluctant to let him commit his refactor of a core part of the system when he can't even explain the basic functionality of that component.