Double sensors from MQTT

I have recognized, that my 3 zigbee-sensor - connected via zigbee2mqtt - are double and I have no idea why.
I’m using the MQTT integration ad there I see 3 devices and 14 entities - which is okay. But when I dig in, I see the the sensors are named with _2 at the end.
i.e. sensor.xiaomismart_1_temperature_2

When I go to Setting/Entities I see sensor.xiaomismart_1_temperature and sensor.xiaomismart_1_temperature_2: the first from integration and the second from MQTT.

Same for the other entities.

I assume that’s caused by my template sensor which I use to correct and round the value.

# Xiaomi Temperatur- und Luftfeuchtigkeits-Sensor
  - platform: mqtt
    name: "XiaomiSmart-1 Temperature"
    state_topic: "zigbee2mqtt/XiaomiSmart-1"
    unit_of_measurement: '°C'
    value_template: "{{ (value_json.temperature + 0.2) | round(1) }}"
    availability_topic: "zigbee2mqtt/bridge/state"
    device_class: "temperature"

How could I clean up and get rid of the double sensors? Is there another option to correct and round without doubling sensors?