async_register_callback never gets called

[bilogic]

import asyncio

from homeassistant.components import bluetooth
from homeassistant.components.bluetooth import BluetoothChange, BluetoothServiceInfoBleak
from homeassistant.core import callback

TARGET_DEVICE_ADDRESS = "11:22:33:44:55:66"

@callback
async def _async_discovered_device(service_info: BluetoothServiceInfoBleak, change: BluetoothChange) -> None:
    """Callback function to handle discovered Bluetooth devices."""
    log.info(f"Bluetooth device discovered: {service_info.name} at {service_info.address}, Change type: {change}")

@service
async def ble_scan(action=None, id=None):
    """Register the Bluetooth callback function."""
    try:
        cancel_callback = bluetooth.async_register_callback(
            hass,                           
            _async_discovered_device,       
            {"address": TARGET_DEVICE_ADDRESS},
            bluetooth.BluetoothScanningMode.PASSIVE
        )
        log.info("Bluetooth discovery callback registered successfully.")

        await asyncio.sleep(10) # Scan for 10 seconds

        # Store cancel_callback in a global var if you need to unregister later
        # global my_cancel_callback
        # my_cancel_callback = cancel_callback
    except Exception as e:
        log.error(f"Failed to register Bluetooth callback: {e}")

    log.info("ble_scan ended")

How do I make the above work? _async_discovered_device never gets called back