Hum, why upgrade the beta ???
With identical settings
Beta 4.12.1.40
Nice color
Beta 4.12.1.117
Blah color
Fixed seriusly ???
Fixed an issue where colors in Render Settings (NVIDIA Iray) > Environment group (e.g., Matte Fog Visibility Tint, Matte Fog Brightness Tint) were being sent to the renderer with their respective green and blue component values transposed