MQTT Light brightness_command_topic sends an unexpected default vaule

Does anyone know why my custom mqtt light would send a value of 3 when I start listening to the brightness_command_topic? It only sends it once, and not again unless I execute an actual action on the light.

  - name: "R2D2 Holoprojector"
    unique_id: "r2d2_df12b4032fe411e4800bcd1fd09bffdc"
    state_topic: "homeassistant/switch/r2d2/holoprojector/state"
    command_topic: "homeassistant/switch/r2d2/holoprojector/switch"
    brightness_state_topic: "homeassistant/switch/r2d2/holoprojector/brightness"
    brightness_command_topic: "homeassistant/switch/r2d2/holoprojector/brightness/set"
    on_command_type: "brightness"
    optimistic: false
    retain: false
    brightness_scale: 255
    payload_on: "ON"
    payload_off: "OFF"

My desired behavior would be to not send anything, or if it “has” to send something a 0 or “OFF” would suffice.

EDIT: Added desired behavior.

Still struggling with this. Does anyone care to share a theory?