Material Instance Platform Stats don't update when Material Layer parameters are changed

The instruction count appears to update properly if the whole asset editor is closed and reopened.

1. Create a new Material Layer asset
2. In that graph, create a Static Switch Parameter which inputs to the Base Color of the Set Material Attributes node
3. Create a Constant3 and plug it into the False input of the Static Switch Parameter
4. Create a Noise expression, and plug it into the True input of the Static Switch Parameter
5. Create a new Material, and in it enable "Use Material Attributes"
6. Create a new Material Attribute Layers expression and connect its output to the Material Attributes input on the main material node
7. In the Material Attribute Layers node, add your Material Layer as the background material
8. Create a new Material Instance based on this material
9. In the Material Instance editor, enable the Platform Stats panel
10. Click over the Layer Parameters panel, and open up the Background layer and toggle your static switch parameter off and on. Observe the Pixel Shader Instruction count not changing.