Download the licensee assets here - [Link Removed]
Place the folder "QualitySwitch" in the content folder of a project and open TST_QualitySwitch.umap
The left hand sphere will be a bold colour, the right hand one will be black. Go to the settings icon at the top -> Material Quality Level and change it, the colour of the left sphere will change, but the right one remains black.
For comparison, open the material of the top layer (ML_TST_QualitySwitch.uasset) and disconnect the quality switch from the emissive color in the SetMaterialAttributes node, and replace it with one of the 4 colours directly (i.e. circumvent the Quality Switch). The right sphere will now have the specified colour.
There's no existing public thread on this issue, so head over to AnswerHub just mention UE-119314 in the post.