Subsurface Profile - Full resolution skin shading blows out results from ambient cubemap

Since the change to Subsurface Profile shader in 4.14 their use with ambient cubemaps have started giving blown out results that come back either white or very desaturated in the viewport. The current workaround is for users to revert back to the old behavior by entering r.sss.checkerboard 0 as a Cvar. This uses the old method.

Related to UDN question posted here.

https://udn.unrealengine.com/questions/329384/skin-shader-looks-wrong-and-blue-after-upgrade-fro.html

1. Open any project
2. Create a subsurface material and apply to a sphere in the scene
3. Add a postprocess volume with an ambient cubemap applied
4. Increase the intensity of the ambient cubemap

RESULT
The subsurface material will turn white no matter what the base color is.

EXPECTED
The subsurface material's basecolor gets influenced by the ambient cubemap but not such that it turns white.