Error "duplicated mapping key (64:5)" in blueprint

I’m trying to create a basic blueprint, but it doesn’t seem to work. When I edit the blueprint with file editor, I get an error message. I don’t know if that’s the reason, but I guess it’s a good place to start by making that message disappear. However, I don’t really understand why it’s there.

Here is the blueprint so far (scroll down for the error message):

blueprint: 
    name: Paulmann 4 Button Wall Switch
    description: Create automations for the Paulmann Wall Switch with four buttons
    domain: automation
    input:
        paulmann_switch:
            name: Paulmann Switch
            description: Select the Switch
            selector:
                device:
                  filter:
                    - integration: zha
        light_target_left:
            name: First Light
            description: Select the light that will be controlled via the buttons on the left side of the switch.
            selector:
                entity:
                    domain:
                        - light
        light_target_right:
            name: Second Light
            description: Select the light that will be controlled via the buttons on the right side of the switch.
            selector:
                entity:
                    domain:
                        - light
mode: single
trigger:
  - device_id: !input paulmann_switch
    domain: zha
    platform: device
    type: remote_button_short_press
    subtype: button_1
    id: A_on_shortpress
  - device_id: !input paulmann_switch
    domain: zha
    platform: device
    type: remote_button_short_press
    subtype: button_2
    id: A_off_shortpress
  - device_id: !input paulmann_switch
    domain: zha
    platform: device
    type: remote_button_short_press
    subtype: button_3
    id: B_on_shortpress
  - device_id: !input paulmann_switch
    domain: zha
    platform: device
    type: remote_button_short_press
    subtype: button_4
    id: B_off_shortpress
condition: []
action:
    if:
      - condition: trigger
        id:
          - A_on_shortpress
    then:
      - service: light.turn_on
        data: {}
        target:
          entity_id: !input light_target_left
    if:
      - condition: trigger
        id:
          - A_off_shortpress
    then:
      - service: light.turn_off
        data: {}
        target:
          entity_id: !input light_target_left
    if:
      - condition: trigger
        id:
          - B_on_shortpress
    then:
      - service: light.turn_on
        data: {}
        target:
          entity_id: !input light_target_right
    if:
      - condition: trigger
        id:
          - B_off_shortpress
    then:
      - service: light.turn_off
        data: {}
        target:
          entity_id: !input light_target_right

And here is the error message:

duplicated mapping key (64:5)

 61 |         data: {}
 62 |         target:
 63 |           entity_id: .input light_t ...
 64 |     if:
----------^
 65 |       - condition: trigger
 66 |         id:

Any recommendations on what to do here?

You need to build the automation logic as an automation first, get that functioning with real data there instead of variables, then convert that to a BP when you have the logic working.
Creating an automation blueprint - Home Assistant.

That said your automation problem is that you can only have 1 ‘if’ sequence in a block. If you need multiple branches/decisions, you need to use a choose statement. Also the if statements have an indentation error. So you have multiple problems there. That is why you need to solve the automation problems before you try to add the blueprint substitution syntax problems or you will have no idea what the error messages are talking about.
Script Syntax - Home Assistant.

Thank you for your response. Good idea to reconstruct everything with a choose statement. That solved it.

However, what you wrote about if-statements does not seem to be entirely correct, because I actually did create the blueprint in exactly the way you described. The automation it is based on works fine and consists of the same four if-statements as the version of the blueprint I posted here. I also have more than one automation that has multiple if-statements and none of them cause any problems. Weird - but the important thing is that it works now.