Error in huesatToRGB when attempting to use color WebcoRE piston to fade color with Inovelli RGBW light

I want to gradually fade my RGBW light colors every few minutes/hours.
I have a WebcoRE piston set up that works properly to change colors, but fade hue produces an error. In the example below, the fade operation fails, but the set color works (but does not fade).

The error looks like:

6:13:12 PM: error groovy.lang.MissingMethodException: No signature of method: static java.lang.Math.round() is applicable for argument types: (null) values: [null]
Possible solutions: round(float), round(double), find(), rint(double), find(groovy.lang.Closure), random() @line 334 (huesatToRGB)

Is there another way to make this fade scenario work?
Is this API expected to work with Inovelli RGBW lights?