How to handle inefficient collegue who is nice with you?

I have a colleague who is terribly inefficient at work. She breaks the code all the time and her code throws runtime errors all the time. While I do my due diligence during code reviews, it’s hard for me to justify it all the time. Most of the time, I end up fixing her issues. I do communicate the scope of improvement every time I review her code and add a dozens of basic review comments. While she does fix the issues, she doesn’t follow basic rules. I expect better from her being 11-12 years experienced software engineer. Having said that, she speaks to me nicely and she is always friendly with the team. I have given her feedback multiple times in a friendly manner and she does seem to take it positive. But I don’t see that getting reflected in her work. She keeps repeating the same mistakes. She simply doesn’t think the big picture while coding. Applies point fix and makes it work temporarily, screwing the other features of application. My manager is overly chilled guy. He hardly cares about my code or her code. He doesn’t understand any code and talking to him in a technical language is a waste of time. Even if we encounter a production issue, my manager doesn’t show any signs of concerns. How do I deal with this situation?