In this DTH, color loop is implemented using Move Hue zigbee command. There isn’t an equivalent Move Color Temperature command, only a Move To Color Temperature.
You can simulate a color temperature loop by using Move To Color Temperature with a long transition time, capturing the color temperature message. When 2000K is achieved, you would need to issues a Move To Color Temperature to 6000K and vice versa. (That’s how the Pulse feature is implemented. When level is 5%, the DTH asks for level to be set to 99% and vice versa.) It may or may not work. I was surprised that the Pulse feature ended up working.