"Color Backfaces" over-exposes materials when turned on

Hi McNeel
I was having a hard time figuring out why there was such a discrepancy between my Cycles view and a rendered viewport in the WIP, the latter being over-exposed. I finally figured out that when I have “Color Backfaces” turned on in the settings for Rendered, the material gets over-exposed. The effect is more visible for plastic and paint materials, not so much for metals and not at all for Plaster/diffuse - could be an indication of something going wrong with reflections?
-Jakob

SysInfo
Rhino 7 SR0 2020-1-21 (Public Build, 7.0.20021.12255, Git hash:master @ bdc08500fd070c4e25152ea118c79846c23b096a)
License type: Commercial, build 2020-01-21
License details: Cloud Zoo. In use by: Jakob Normand ()
Expires on: 2020-03-06

Windows 7 SP1 (Physical RAM: 32Gb)
Machine name: NIK-Z620

Non-hybrid graphics.
Primary display and OpenGL: NVIDIA GeForce GTX 1080 Ti (NVidia) Memory: 11GB, Driver date: 12-24-2019 (M-D-Y). OpenGL Ver: 4.6.0 NVIDIA 441.87

OpenGL Settings
Safe mode: Off
Use accelerated hardware modes: On
Redraw scene when viewports are exposed: On

Anti-alias mode: 4x
Mip Map Filtering: Linear
Anisotropic Filtering Mode: Height

Vendor Name: NVIDIA Corporation
Render version: 4.6
Shading Language: 4.60 NVIDIA
Driver Date: 12-24-2019
Driver Version: 26.21.14.4187
Maximum Texture size: 32768 x 32768
Z-Buffer depth: 24 bits
Maximum Viewport size: 32768 x 32768
Total Video Memory: 11 GB

Rhino plugins
C:\Program Files\Rhino WIP\Plug-ins\Commands.rhp “Commands” 7.0.20021.12255
C:\Program Files\Rhino WIP\Plug-ins\WebBrowser.rhp “WebBrowser”
C:\Program Files\Rhino WIP\Plug-ins\rdk.rhp “Renderer Development Kit”
C:\Program Files\Rhino WIP\Plug-ins\RhinoScript.rhp “RhinoScript”
C:\Program Files\Rhino WIP\Plug-ins\IdleProcessor.rhp “IdleProcessor”
C:\Program Files\Rhino WIP\Plug-ins\RhinoRenderCycles.rhp “Rhino Render” 7.0.20021.12255
C:\Program Files\Rhino WIP\Plug-ins\RhinoRender.rhp “Legacy Rhino Render”
C:\Program Files\Rhino WIP\Plug-ins\rdk_etoui.rhp “RDK_EtoUI” 7.0.20021.12255
C:\Program Files\Rhino WIP\Plug-ins\rdk_ui.rhp “Renderer Development Kit UI”
C:\Program Files\Rhino WIP\Plug-ins\NamedSnapshots.rhp “Snapshots”
C:\Program Files\Rhino WIP\Plug-ins\Alerter.rhp “Alerter”
C:\Program Files\Rhino WIP\Plug-ins\RhinoCycles.rhp “RhinoCycles” 7.0.20021.12255
C:\Program Files\Rhino WIP\Plug-ins\Toolbars\Toolbars.rhp “Toolbars” 7.0.20021.12255
C:\Program Files\Rhino WIP\Plug-ins\3dxrhino.rhp “3Dconnexion 3D Mouse”
C:\Program Files\Rhino WIP\Plug-ins\Displacement.rhp “Displacement”
C:\Users\jn\AppData\Roaming\McNeel\Rhinoceros\packages\7.0\rhino-render-next\0.0.2\RhinoRenderNext.rhp “Rhino Render Next” 0.0.2.0
C:\Users\jn\AppData\Roaming\McNeel\Rhinoceros\packages\7.0\rhinopbrmaterial\1.1.0\RhinoPbrMaterial.rhp “RhinoPbrMaterial” 1.1.0.0
C:\Program Files\Rhino WIP\Plug-ins\import_ZPR.rhp “ZCorp Import”
C:\Program Files\Rhino WIP\Plug-ins\export_ZPR.rhp “ZCorp Export”
C:\Program Files\Rhino WIP\Plug-ins\digitize_MicroScribe.rhp “MicroScribe Digitizer”