Why does toggling a group toggles each lamp individually (and not the whole group)?

I have the following automation. These are two switches (the first two entries); they are also grouped together. The third automation is supposed to work on that group as a whole:

- id: 'wall_switch_ch3_lampe_gauche'
  initial_state: True
  trigger:
    - platform: state
      entity_id: sensor.rf433_switch_payload_full
  condition:
    condition: template
    value_template: "{{ states.sensor.rf433_switch_payload_full.state[-6:] == '1A97E2' }}"
  action:
    data:
      entity_id: light.ch3_lampe_gauche
    service: homeassistant.toggle
    
- id: 'wall_switch_ch3_lampe_droite'
  initial_state: True
  trigger:
    - platform: state
      entity_id: sensor.rf433_switch_payload_full
  condition:
    condition: template
    value_template: "{{ states.sensor.rf433_switch_payload_full.state[-6:] == '1F97E9' }}"
  action:
    data:
      entity_id: light.ch3_lampe_droite
    service: homeassistant.toggle

- id: 'wall_switch_ch3_all_lamps'
  initial_state: True
  trigger:
    - platform: state
      entity_id: sensor.rf433_switch_payload_full
  condition:
    condition: template
    value_template: "{{ states.sensor.rf433_switch_payload_full.state[-6:] == '5A4BE1' }}"
  action:
    data:
      entity_id: group.ch3
    service: homeassistant.toggle

For the sake of completeness, the group:

 ch3:
    entities:
      - light.ch3_lampe_gauche
      - light.ch3_lampe_droite

What happens is that when the 5A4BE1 signal is received (approximately speaking), the third automation fires and toggles the state of each switch separately.
In other words, when both switches are off or on - everything is OK (they both turn to the other state), but when one of the switches is on while the other is off, the former flips to off and the latter to on (and vice versa). Instead of both turning on or off, depending on the state of the group.

Why is it so?

See How to access a card toggle as an entity?