Using a Shading Model node set to Unlit results in an invalid material with FromExpression domain

1. Create a material
2. Set its domain to From Expression
3. Recreate the node graph as in the screenshot

Note that the preview sphere is black.

Adding a ShadingModel node set to Unlit to a Material with From Expression domain causes the material to be wrong.

For example in this simple material

[Link Removed]

The preview sphere is expected to be yellow but it is black instead. Deleting the Unlit ShadingModel node will fix the material.

UDN for reference: https://udn.unrealengine.com/s/case/500QP000005WkrGYAS/unlit-shading-model-node-correctly-not-working-when-trying-to-switch-or-blend-between-two-shading-models?fromCase=1