Axis-locked billboards with parent rotation?

I followed this tutorial to make a camera-facing billboard that’s locked on one axis and it worked fine.

However when the object with the billboard is the child of something with a non-zero rotation, the billboard no longer faces the camera.

Is there a way to fix this?

I know this thread is one hundred years old, but I also got caught out by this. What you want to do is set “absolute rotation” to true on your material billboard component.