Min Roughness Light Setting Does Not Work In Forward Shading

Min roughness in the light settings currently aren't working in the forward shading mode.

1. open a blank project
2. Enable forward shading in project settings > restart
3. Once editor is back up create a material with 0 roughness
4. Compile and apply material to any object in the default scene so that you can see the specular highlight
5. Select the directional light and change the min roughness value to 1

RESULT
The specular highlight appears as though the roughness is still 0

EXPECTED
The Highlight grows and fades away as the min roughness value increases simulating an increase in the materials roughness