I'm pretty sure I don't understand it. Maybe sending a screenshot of your scene would make this more clear. Or maybe a bit more of the code?
Generally if you rotate parent node, all child nodes will move with it to stay on the same place relative to parent. If you need to rotate just a child node, you run ChildNode.rotate() and it will rotate itself without modifying parent.
I'm making a wild guess here, that if you rotate parent, you rotate it not horizontally, but vertically, and they your child node (pivot?) it upside down and "rotate left" is still valid in its point of reference.
Imagine looking at spinning Earth and then looking at it upside-down. It still spins in same direction, but you see it differently.