Zemismart Recessed Light won't color switch with Alexa

So we are renovating a house and my plan is to do all lights via zigbee. So I bought 2 of these Zemismart Downlights to test them:
I connected them successfully to the newly aquired HE. Everything is controllable as it should be. So I activated the Alexa App and let it use the downlight. Alexa finds the Downlight and I can control switching it on and off and also dim it.
Only thing I can't do is change the color via Alexa.
Has anybody got an idea why or what I could change to make it work?

Forgot to mention: The light is currently flagged as type "Generic Zigbee RGBW Light" in HE.

Hello. Welcome to Hubitat!

Can you control the color of the light from the edit device page in HE?

I can, yes. That's what confuses me.

Also I didn't mention: When I turn on the bulb (I mean electrically turning it on by a awitch) and I tell Alexa to switch the color to a different one, the light flashed shortly in a seamingly random color. But just for a brief moment until it switch back to the original color.

But this is only from Alexa? That doesn't sound right. The control from Alexa is the same as from the device itself. I would contact support@hubitat.com