Hue integration: why some lights/rooms don't have brightness?

Configuration
1

Hi:
Some of my automations rely on brightness of rooms/lights and works randomly, so I digged into it and found that some of my rooms/lights have brightness values, others don’t. All my lights are Philips Hue and I can’t figure out any pattern why some lights have lots of null values like below:

min_color_temp_kelvin: 2000
max_color_temp_kelvin: 6535
min_mireds: 153
max_mireds: 500
effect_list: off, candle, fire, prism, sparkle, opal, glisten, underwater, cosmos, sunbeam, enchant, sunrise, sunset
supported_color_modes: color_temp, xy
effect: null
color_mode: null
brightness: null
color_temp_kelvin: null
color_temp: null
hs_color: null
rgb_color: null
xy_color: null
mode: normal
dynamics: none
friendly_name: Ceiling Lamp
supported_features: 44

And a similar color bulb in another room does get brightness and other values:

min_color_temp_kelvin: 2000
max_color_temp_kelvin: 6535
min_mireds: 153
max_mireds: 500
effect_list: off, candle, fire, prism, sparkle, opal, glisten, underwater, cosmos, sunbeam, enchant, sunrise, sunset
supported_color_modes: color_temp, xy
effect: off
color_mode: xy
brightness: 255
color_temp_kelvin: null
color_temp: null
hs_color: 38.88, 49.02
rgb_color: 255, 211, 130
xy_color: 0.445, 0.4067
mode: normal
dynamics: none
friendly_name: XX Ceiling Lamp
supported_features: 44

Does anybody know if it’s a bug with integration or something I’m doing wrong here? Many thanks!

2

What kind of Philips Hue products do you have in those groups?
White Bulb?
White ambiance bulbs?
Color bulbs?
Light strips?
Any smart plugs?

3

Thanks for your reply! I figured out, it’s because the lights are off (stupid me).
I’m trying to do something generic to control light transition from one color to another then off (sunset with color transition), I cannot use light.trun_off as it doesn’t support color transition, light.trun_on with brightness 0 also doesn’t work as it ignores HS/RG values.
The problem is that since it’s a generic script, it needs to run in parallel. And in rare case a transition can be restarted, which mean before 2nd transition is done, it’s turned off by the previous run.
My idea was to use brightness, and it fails as it’s set immediately when transition starts. I then tried check last_changed, didn’t work either, when new transition starts the on/off state is not changed. Also last_updated seems to change more than what I expect.
Would be nice in HA to allow restart of a script conditionally - based on the entity in control for example.