Hi, looking at it here, a Group Master doesn't affect I Amber or I White when using the Intensity parameters. When using the color parameters, CMYAW, it does seem to work looking in the DMX Output window. Are you using the Intensity parameters or Color parameters?
It is likely a limitation tied to the color system, Amber and White are also ignored by the Color Picker. They are currently working on to make improvements in the color system in a future software release.
This was using intensity parameters. As you say it works fine using CMY but I would expect it to work for I white and I amber, the same as it does for I red, I green and I blue.
