It doesn't push back enough when I ask it to implement something that is a bad idea. I've caught it breaking threading code, and then fixing it by putting atomic in the wrong place: which might have fixed in that a few racey tests can now run a thousands times, but it wasn't the right place and so the race still exist. It has changed constants when moving the constant to a different file (the move was required, but the constant were not expected to change).

I have found it very helpful to ask AI to review the latest changes - it often finds serious problems in review of code it just wrote.