Master Sound Class Volume Changes not Propagating to Child Sound Classes

Changing the volume of the Master sound class does not propogate to children when using the 'Set Sound Mix Class Override' node within blueprints.

1. Download and Open attached project.
2. Press PIE
3. Move the 'Music' slider and observe how the volume changes.
4. Move the 'Master' slider.

Outcome No change in volume for the music currently playing.

Expected The music volume should lower since the Music sound class is a Child of the Master Sound Class.