You "personally checked" the result (generated by an LLM, a huge black box with extensive knowledge of all fields) to the best of your knowledge. There is a mismatch between what the machine knows (and has done as the result of it) and what you think you know.

Implementing a fix implies knowledge of the inner workings that brought you to it. A fix made by a LLM does not give you that.

Why do I argue here anyway? :)

Before sending it I have tried the patch locally. It worked.

So I sent the proposal. And it was accepted by the author.