Z2M: Button events "single" on power up

I use the event feature for buttons in Z2M 2.x version. I’ve noticed that on HA power-up, the “event” is fired as single press and my automations run.

I had to add the condition for trigger.from_state.state not in ['unknown', 'unavailable'] but this sounds wrong approach to me, for something that fires the events and doesn’t have a state.

triggers:
  - entity_id:
      - event.sonoff_snzb_01_button_1_washing_machine_action
    trigger: state
    attribute: event_type
    to: single
conditions:
  - condition: template
    value_template: "{{ not trigger.from_state.state in ['unknown', 'unavailable'] }}"

Is this normal that event is fired on power up?

See: Using the new action events in Zigbee2MQTT 2.0