Modulate Blend Mode on Deferred Decals does not seem to multiply with background pixels

Modulate Blend Mode on Deferred Decals does not blend multiply with background pixels. Transparency for Deferred Decals also does not seem to match with what occurs in 4.27;

Repro Rate: 4/4

Tested this in //UE4/Release-4.27 @ CL#18319896 and could not get a similar result. Though I'm unable to fully regression test as in EA and 4.27, modulate was not supported for Deferred Decals.

1. Create a new Blank BP project
2. In the Content Browser, create and open a new Material
3. Create a Constant4Vector node
4. Hook up the node to the Base Color input
5. In Details, change the following properties:
   • Material Domain: Deferred Decal
   • Blend Mode: Modulate
6. Save & Apply then close the Material Editor
7. Drag a Decal Actor into the scene
8. Set the material to your Decal & observe

Results: The decal, instead of making the underlying geometry darker, simply acts like a default lit decal.
Expected: Decal should should make the underlying geometry darker.