XY and brightness on Hue lamps processed as two commands?

I control several Phillips Hue lamps with Zigbee2Mqtt by sending the brightness, x and y value because those are the only values that are updated in the state topic with these lamps. I now noticed that when I power off a lamp with e.g. the color green and then send the xy values for the color red and brightness 100 in one message the lamp first turns on with a green color and only after that it turns red. This becomes really clear when also a a transition time is sent in the message.

Is there an explanation for this behaviour or is there a better way to directly change the xy color and turn on the lamp without this additional color transition?