Custom Depth Post Process Stencil does not work with Material Billboard on Actors

MaterialBillboardComponent does not render with CustomDepth material in PostProcessVolume as other objects do.

Found in 4.16.3 CL 3561208, 4.17.2 CL 3658906, 4.18.1 CL 3454814

1. Create New Blank Project, no Starter Content
2. Create new Material where allow CustomDepth Writes = True
3. Apply a MaterialBillboardComponent to the actor with the new Material
4. On the MaterialBillboardComponent, set the Render CustomDepth Pass = True
5. Make PostProcessMaterial as shown in image
6. Use this PostProcessMaterial in the PostProcessVolume

Expected: Actor with MaterialBillboardComponent will render in Play Mode
Result: Actor with MaterialBillboardComponent will not render in Play Mode