> And sometimes it changed the existing code base to make its new code "pass", when it actually should fix its own code instead.

I haven’t tried MiniMax, but GPT-5.2-Codex has this problem. Yesterday I watched it observe a Python type error (variable declared with explicit incorrect type — fix was trivial), and it added a cast. (“cast” is Python speak for “override typing for this expression”.) I told it to fix it for real and not use cast. So it started sprinkling Any around the program (“Any” is awful Python speak for “don’t even try to understand this value and don’t warn either”).