Syntax Check: Trigger script at specific time

OK, so this isn’t working.

alias: "managed_afternoon"
    initial_state: 'on'
    trigger:
      platform: time
      at: '12:05:00'
    action: 
      - service: scene.turn_on
        entity_id: scene.warm_white

It says that “AT” is not a valid option for “Trigger”.

Also, althought it doesn’t load the automation, my lights turn to full brightness and blue at 12:05AM. So the wrong thing is triggered at the wrong time. See any problems with the syntax?

Are you running latest version of HA? Change to ‘at’ has been on latests versions.

I keep it up-to-date. What was the change?

I mean the ‘at’ was introduced few versions ago, but if you have HA version up to date, maybe there’s another mistake in your config.
Do you have another automation with time triggering?

This is the closest. It matches the lighting to an outdoor RGB sensor every 5 minutes. Otherwise, I don’t actually have “At” being used anywhere else.

alias: "managed_morning"
initial_state: 'on'
trigger:
  platform: time
  minutes: '/5'
  seconds: 00
condition:
  condition: time
  before: '12:00:00'
action: 
  service: script.matchlights

I have the folowwing that works perfectly

- alias: 'Reset morning light automation'
  initial_state: True
  trigger:
    - platform: time
      at: '0:01'
  condition:
    - condition: state
      entity_id: automation.switch_lights_on_in_the_morning
      state: 'off'
  action:
    - service : automation.turn_on 
      entity_id: automation.switch_lights_on_in_the_morning  

I think you have too much indent between your alias and trigger. Also no need to put the seconds in your at condition.
Try

alias: "managed_afternoon"
  initial_state: 'on'
  trigger:
    platform: time
    at: '12:05'
  action: 
    - service: scene.turn_on
      entity_id: scene.warm_white

Mine also works fine, I used double quote instead of single quote for time. Here is my example:

# Front Lights Off at 11PM
- id: front_lights_off_at_11_night
  alias: front lights off at 11 night
  trigger:
    platform: time
    at: "23:00:00"
  action:
    service: homeassistant.turn_off
    entity_id: switch.maindoor

However I am still struggling with multiple conditions in my automation rules. I have AND, OR in my conditions and automation editor complains that ‘Conditions are not supported yet’.