Fake "press" event during MQTT Automation Trigger Registration

I am trying to create an MQTT device trigger per the instructions here:

Here is my registration JSON payload that sets up the trigger:

{
  "t": "cmd/test/primary",
  "type": "button_short_press",
  "stype": "turn_on",
  "device": {
    "ids": "TestId",
    "name": "Test Device",
    "mf": "Test Man",
    "mdl": "Test Model",
    "hw": "1.0",
    "sw": "1.0",
    "sa": "Somewhere",
    "sn": "TODO1234"
  },
  "pl": "pushed",
  "atype": "trigger",
  "p": "device_automation"
}

However I am running into an issue that Home Assistant appears to send a fake “press” event whenever a the trigger is auto-discovered / registered.

I have been able to work around the issue by changing the payload from: “press” → “pushed”. Hence I can filter out the annoying “press” event by adding a condition, as follows:

alias: Trigger Test
description: ""
triggers:
  - domain: mqtt
    device_id: 5d4b5d319a572db91de47564dd056b1a
    type: button_short_press
    subtype: turn_on
    metadata: {}
    trigger: device
conditions:
  - condition: template
    value_template: "{{ trigger.payload == 'pushed' }}"
actions:
  - action: light.turn_on
    metadata: {}
    data:
      brightness_pct: 100
    target:
      device_id: 6d5f3d7db5ca35664899489df309c38f
mode: single

Although the configuration above works, it feels like I have missed something.

Is there a simpler way to configure “momentary” buttons, i.e. buttons that don’t have a state like normal On/Off switches?