Mqtt fan state_value_template issue , unknown status

hi,
i m unable to get something as i activate the state_value_template config line. even the elese condition never returns anything.
the device is a sonoff dual , driving my extraction fan at home.

here the config :
if i just select a state_topic containing a string that is on or off, it just works, but i would like to use the templating to have a more standardized config on the device.
note the condition itself is just for testing purposes
i also have the same issue for the preset mode i think.
appart testing in the jinja template , is there anywhere else to find logs ? i activated mqtt logs but dont get anything about that.

  fan:
    - name: "bathroom-fan"
      unique_id: "fan.bathroom-fan"
      command_topic: 'cmnd/vmc/event'
      #availability:
       # - payload_available: 'Online'
       # - payload_not_available: 'Offline'
      #  - topic: 'tele/vmc/LWT'
      availability_topic: 'tele/vmc/LWT'
      payload_available: 'Online'
      payload_not_available: 'Offline'
      state_topic: 'tele/vmc/STATE'
      state_value_template: >
       {%- if "OFF" in value_json.POWER1 and "OFF" in value_json.POWER2 -%}
       "off"
       {%- else -%}
       "on"
       {%- endif %}
      preset_mode_command_topic: 'tele/vmc/STATE'
      preset_mode_command_template: >
       {%- if 'off' in value -%}
       speed0
       {%- elif 'low' in value -%}
       speed1
       {%- elif 'high' in value -%}
       speed2
       {%- else -%}
       speed1
       {%- endif %}
      #percentage_command_topic: 'cmnd/vmc/event'
      #percentage_command_template: >
      #   {% if value < 10 %}
      #      speed0
      #   {% elif value < 80 %}
      #      speed1
      #   {% else %}
      #      speed2
      #   {% endif %}
      #percentage_state_topic: 'tele/vmc/STATE'
      preset_modes:
        -  "off"
        -  "low"
        -  "high"
      preset_mode_value_template: >
       {%- if "OFF" in value_json.POWER1 and "OFF" in value_json.POWER2 -%}
        "off"
       {%- elif "ON" in value_json.POWER1 and "OFF" in value_json.POWER2 -%}
        "low"
       {%- elif "OFF" in value_json.POWER1  and "ON" in value_json.POWER2 -%}
        "high"
       {%- endif %}
      #percentage_value_template: >
      #   {% if value_json.POWER1 == "OFF" and value_json.POWER2 == "OFF" %}
      #   0
      #   {%- elif value_json.POWER1 == "ON" and value_json.POWER2 == "OFF" -%}
      #   50
      #   {%- elif value_json.POWER1 == "OFF" and value_json.POWER2 == "ON"  -%}
      #   100
      #   {%- endif %}
      payload_on: "on"
      payload_off: "off"

the payload in tele/vmc/STATE :

{"Time":"2023-08-23T18:02:06","Uptime":"32T06:02:37","UptimeSec":2786557,"Heap":24,"SleepMode":"Dynamic","Sleep":50,"LoadAvg":19,"MqttCount":37,"POWER1":"ON","POWER2":"OFF","Wifi":{"AP":1,"SSId":"ouinouin_Nicol","BSSId":"A4:2B:B0:A5:A0:48","Channel":11,"Mode":"11n","RSSI":58,"Signal":-71,"LinkCount":2,"Downtime":"0T09:56:14"}}