Synchronize the on/off state of 2 entities - Single Run Mode

Simple blueprint copied from Adrien Chevrier Synchronize the on/off state of 2 entities to synchronize the state of 2 entities. But this one use the “Single Run Mode”.

blueprint:
  name: Synchronize states
  description: 'Synchronize the on/off state of 2 entities'
  domain: automation
  input:
    entity_1:
      name: First entity
      selector:
        entity:
    entity_2:
      name: Second entity
      selector:
        entity:
mode: single
max_exceeded: silent
variables:
  entity_1: !input 'entity_1'
  entity_2: !input 'entity_2'
trigger:
  - platform: state
    entity_id: !input 'entity_1'
  - platform: state
    entity_id: !input 'entity_2'
condition:
  - condition: template
    value_template: '{{ states(entity_1) != states(entity_2) }}'
action:
  - service: homeassistant.turn_{{ trigger.to_state.state }}
    data:
      entity_id: '{% if trigger.from_state.entity_id == entity_1 %} {{ entity_2 }} {% else %} {{ entity_1 }} {% endif %}'

Stop working after upgrade to core-2021.4.6