Yeelight brightness_step_pct

1 
- alias: CubeEventRotateOn
  initial_state: true
  trigger:
    platform: state
    entity_id: sensor.xiaomi_cube_action
    to: 'rotate_left'
  action:
  - data:
      brightness_step_pct: 10
    entity_id: light.ikea_bulb_bedside_light
    service: light.turn_on

The above code works from a IKEA bulb but if I change this to a yeelight it breaks. When I rotate to the left the yeelight turns on, after a second rotate to the left and the light goes from 10% to 100%. why?

- alias: CubeEventRotateOn
  initial_state: true
  trigger:
    platform: state
    entity_id: sensor.xiaomi_cube_action
    to: 'rotate_left'
  action:
  - data:
      brightness_step_pct: 10
    entity_id: light.desk_yeelight
    service: light.turn_on