False readings using BLE with xiaomi band 5

Hello,
I’m trying to set up a presence detection system using an ESP32 and a Xiaomi mi band 5.
I have random positive and I dont’ understand the reason:

# Configure Bluetooth tracking
bluetooth_proxy:
  active: true

# Tracker BLE
esp32_ble_tracker:
  scan_parameters:
    interval: 3200ms  
    window: 1200ms    
    passive: true 

#  RSSI  Mi Band 5
sensor:
  - platform: ble_rssi
    id: miband5_rssi
    mac_address: "AA:BB:CC:DD:EE:FF"
    name: "Mi Band 5 RSSI"
    filters:
      - median:
          window_size: 3
          send_every: 1
      - sliding_window_moving_average:
          window_size: 3
          send_every: 1
      - timeout: 60s

I was out of home from 21:00 to 21:30 but from the history I see this:

Where those readings come from ?