Card show `NaN` when HA restarted

Configuration
1 
- sensor:
    - name: v_user1_weight
      unique_id: v_user1_weight
      icon: mdi:scale-bathroom
      unit_of_measurement: kg
      device_class: weight
      state: >
        {% set weight = states('sensor.scale_weight') | float %}
        {{ weight if weight >= 50 else this.state }}
      availability: "{{ has_value('sensor.scale_weight') }}"

I use the above to transfer new readings from sensor.scale_weight into v_user1_weight, but whenever I restart HA, v_user1_weight becomes NaN, any idea how I can make it show the last recorded value?

2

Use a triggered template sensor. They are restored after a restart.