Help with MQTT Bulbs with temperature control

Hi,

I have a smartthings unit hooked upto a bunch of z-wave bulbs which have brightness, temperature and on/off controls support via the MQTT bridge to home assistant. I have other regular bulbs and relays which are very easy to control via mqtt but these don’t seem to respond to ha although I can see their topic reponses in ha log when they are triggered via my google assistant or smartthings app. This is my config in the yaml file.

- name: 'Rail Bulb'
platform: mqtt
state_topic: 'smartthings/Rail Bulb/switch/state'
command_topic: 'smartthings/Rail Bulb/switch/cmd'
payload_off: off
payload_on: on
color_temp: true
color_temp_command_topic: 'smartthings/Rail Bulb/colorTemperature/state'
brightness: true
brightness_command_topic: 'smartthings/Rail Bulb/level/state'
brightness_state_topic: 'smartthings/Rail Bulb/level/cmd'
optimistic: false
retain: false

Is there anything I’m missing? One interesting thing I have noticed is that when the bulb is turned off, the brightness is also set to 0 but I dont know how to do it in ha other than the code above. ANy help please?