Unable to automate Zigbee LED strip

Configuration
1

I muse be doing something stupid, I have been trying to test out HA on a Pi3 before I invest in the new HA blue thing.

Anyway, I have been trying to do a test automation with an RGBW strip that runs via Zigbee over Conbee2 (deCONZ), I can see the device, I can control the colour, brightness, tempreture, all that good stuff, but when I try to use the automate function editor it throws a wobbly;

I get the error:
Message malformed: extra keys not allowed @ data[‘rgb_color’]

My automation

type: turn_on
Device_id: 1f57d4bb0d2ba668d8d56d30ba5d1feb
entity_id: light.test_light
domain: light
brightness_pct: 40
rgb_color:
  - 255
  - 255
  - 255

If I try to edit the YAML file directly to add the RGB option it doesn’t like it and breaks, this also happens no matter that I try and add, even if I add a transition timer I get the same issue.

Am I doing something stupid here?

N.B. from the YAML file;

- id: '1613569961461'
  alias: New Automation
  description: ''
  trigger:
  - platform: time
    at: '14:03'
  condition: []
  action:
  - type: turn_on
    device_id: 1f57d4bb0d2ba668d8d56d30ba5d1feb
    entity_id: light.test_light
    domain: light
    brightness_pct: 40
    rgb_color:
  - 255
  - 255
  - 255
  mode: single
2

So I am still unsure what caused it, but I decided to ignore using the automate function in the interface and write it from scratch, this one seems to work ok

#   Test to turn LED strip on at 14:10, white, 30 second transition
- id: Test-on
  alias: "Test strip on"
  trigger:
  - at: '14:10'
    platform: time
  action:
    - service: light.turn_on
      data:
        entity_id: light.test_light
        brightness_pct: 40
        rgb_color: [255,255,255]
        transition: 30