There's a time and place for refactoring, but just fixing an isolated bug isn't it. But I've seen that often AI can't help itself from making changes you didn't ask for.
Before AI, "now" was seen as the wrong place for a refactor because of the time and effort involved, but if the hacky patch of a fix is roughly the same amount of wall clock time as a 500 line proper fix that makes the problem go away forever, what's the argument that the 10 line hack is actually better?
That only makes sense if the coworker isn't validating the fix and no one is reviewing the code. 500 lines of slop is going to take much longer if you have a human in the loop.