Opacity of Translucent Materials in UMG Retainer Box Inconsistent

Using a translucent material with a 0 opacity does not seem to be working when using a retainer box that is attempting to apply it to the image.

When the material is set to additive or masked, it works as expected.

1. Open the editor
2. Create a new Widget Blueprint
3. Add a Retainer Box
4. Add an image parented to the Retainer Box
5. Create a new material (Use the attached screenshot for the setup)
6. Apply the material to the Effect Material of the Retainer Box
7. Add the widget to the viewport in the level blueprint

Result: The image still shows up, even though the material is completely transparent.

Expected: The image would be transparent, having the material applied to it.