Light color cannot be changed via HA automation

[ha-elguano]

I have two Cync wifi lightbulbs. They generally work fine in HA, and I can control on/off, brightness, and color with dashboard controls and within Device/Entity controls.

However, when I try to set color in an automation using the "light.turn_on" action, the light doesn't respond to any color requested. Everything else (on/off, brightness, color temp) seems to work properly.

[logicbus]

I'd like to see this functionality. Obvious use case is the ability to create an automation that changes the color at different times of day.