The problem

I have some light groups in deconz which only contain dimmable lights. For these groups, no brightness attribute is available in home assistant. For groups with temperature or colour, the brightness attribute is reported correctly.

json of the dimmable light group from the REST-API:

{
	"action": {
		"alert": "none",
		"bri": 255,
		"colormode": "hs",
		"ct": 0,
		"effect": "none",
		"hue": 0,
		"on": true,
		"sat": 127,
		"scene": null,
		"xy": [
			0,
			0
		]
	},
	"devicemembership": [],
	"etag": "d818412ae47f1fa502430d6d7668329b",
	"id": "4",
	"lights": [
		"22",
		"8"
	],
	"name": "Kueche",
	"scenes": [],
	"state": {
		"all_on": true,
		"any_on": true
	},
	"type": "LightGroup"
}

state of the dimmable light group in home assistant:

entity: light.kueche
state: on
attributes:
  effect_list:
    - colorloop
  supported_color_modes:
    - brightness
  effect: null
  color_mode: unknown
  brightness: null
  is_deconz_group: true
  all_on: true
  friendly_name: Kueche
  supported_features: 44

What version of Home Assistant Core has the issue?

core-2024.4.3

What was the last working version of Home Assistant Core?

No response

What type of installation are you running?

Home Assistant Container

Integration causing the issue

deconz

Link to integration documentation on our website

https://www.home-assistant.io/integrations/deconz/

Diagnostics information

No response

Example YAML snippet

No response

Anything in the logs that might be useful for us?

No response

Additional information

No response