HA sends (random?) MQTT commantds when connected

Hello.

I ve installed HA a few days ago and just joined the forum!
This is my first post so please bear with me in case i am posting in the wrong section or something is not exactly what is supposed to be.
So heres my case and problem:

I have installed the MQTT broker as an addon in HA and am sendging MQTT commands to an external arduino based system to operate light, heating etc.
See the config.yaml section below:


     -  unique_id: heating_basement_mqtt
       name: "Heating Basement"
       command_topic: "cmnd/pl/1.57.3"
       state_topic: "stat/pl/1.57.3"
       device_class: switch
       state_on: "1"
       state_off: "0"
       payload_on: "1"
       payload_off: "0"
       optimistic: false
       retain: false

    -  unique_id: heating_bedrooms_mqtt
       name: "Heating Bedrooms"
       command_topic: "cmnd/pl/1.31.3"
       state_topic: "stat/pl/1.31.3"
       device_class: switch
       state_on: "1"
       state_off: "0"
       payload_on: "1"
       payload_off: "0"
       optimistic: false
       retain: false       

    -  unique_id: heating_kitchen_mqtt
       name: "Heating Kitchen"
       command_topic: "cmnd/pl/1.46.3"
       state_topic: "stat/pl/1.46.3"
       device_class: switch
       state_on: "1"
       state_off: "0"
       payload_on: "1"
       payload_off: "0"
       optimistic: false
       retain: false

    -  unique_id: heating_LivingRoom_mqtt
       name: "Heating Living Room"
       command_topic: "cmnd/pl/1.45.3"
       state_topic: "stat/pl/1.45.3"
       device_class: switch
       state_on: "1"
       state_off: "0"
       payload_on: "1"
       payload_off: "0"
       optimistic: false
       retain: false
  
     - unique_id: blinds_front_left
       name: "Blinds Front left"
       command_topic: "cmnd/bl/1.11.2"
       state_topic: "stat/bl/1.11.2"
       optimistic: false 
       state_open: "2"
       state_closed: "1"
       state_stopped: "0"
       payload_stop: "0"
       payload_open: "2"
       payload_close: "1"
       retain: false

The problem is that MQTT commands get sent by HA everytime the connection is established with the broker. I have tried to add “retain:false” to make sure that the broker doesn’t sent old messages but that made no apparent difference.
Any ideas?