Triggers Actions from a single MQTT event updating datetime

Configuration
1

I have a datetime time entity that I am looking to push to MQTT, and also update from another MQTT topic if the connected system wants to push a value to HA. I can’t seem to set two datetime entities using a split from the source message. This is my configuration as it stands:

input_datetime:
  pethub_curfew_start:
    name: Curfew Start
    has_time: true
    icon: mdi:clock-start

  pethub_curfew_end:
    name: Curfew End
    has_time: true
    icon: mdi:clock-end

And in Automations I have:

- id: curfewtomqtt
  alias: "Pet Hub Curfew to MQTT"
  trigger:
    platform: state
    entity_id:
      - input_datetime.pethub_curfew_start
      - input_datetime.pethub_curfew_end
  action:
    - service: mqtt.publish
      data:
        topic: pethub/curfewtest
        payload_template: "{{ states('input_datetime.pethub_curfew_start')[0:5] }}-{{ states('input_datetime.pethub_curfew_end')[0:5] }}"

- id: mqtttocurfew
  alias: "MQTT to Pet Hub Curfew"
  trigger:
    - platform: mqtt
      topic: 'pethub/curfewtestset'
  action:
    - service: input_datetime.set_datetime
      target:
        entity_id: input_datetime.pethub_curfew_start
      data:
        time: "{{ trigger.payload.split('-')[0] }}"
    - delay: '00:00:01'
    - service: input_datetime.set_datetime
      target:
        entity_id: input_datetime.pethub_curfew_end
      data:
        time: "{{ trigger.payload.split('-')[1] }}"

The idea is I have a MQTT topic that holds HH:MM-HH:MM for the start / end time, and when either value is changed in HA it publishes to the topic, and vice versa if I publish to MQTT it updates the datetime entities.
The only way I have managed to get this working is to add a delay: '00:00:01' and I was wondering if there was a better / cleaner way.