BLE注销GATT客户端报错是什么原因导致的？

IDF版本5.1.2，GATTC注册代码根据gattc_gatts_coex例程生成：Code: Select all
esp_err_t register_gattc(void){    esp_err_t ret;    ret = esp_ble_gattc_register_callback(esp_gattc_cb);    if (ret)    {        ESP_LOGE(COEX_TAG, "%s gattc register failed, error code = %xn", __func__, ret);        return ret;    }    ret = esp_ble_gattc_app_register(GATTC_PROFILE_C_APP_ID);    if (ret)    {        ESP_LOGE(COEX_TAG, "%s gattc app register failed, error code = %xn", __func__, ret);        return ret;    }    esp_err_t local_mtu_ret = esp_ble_gatt_set_local_mtu(500);    if (local_mtu_ret)    {        ESP_LOGE(COEX_TAG, "set local  MTU failed, error code = %x", local_mtu_ret);        return local_mtu_ret;    }    return ESP_OK;}
正常运行，根据代码写的注销函数：Code: Select all
static esp_err_t unregister_gattc(void){    esp_err_t ret;    // 注销GATT客户端应用    ret = esp_ble_gattc_app_unregister(GATTC_PROFILE_C_APP_ID);    if (ret)    {        ESP_LOGE(COEX_TAG, "%s gattc app unregister failed, error code = %xn", __func__, ret);        return ret;    }    // 注销GATT客户端回调函数    ret = esp_ble_gattc_register_callback(NULL);    if (ret)    {        ESP_LOGE(COEX_TAG, "%s gattc unregister failed, error code = %xn", __func__, ret);        return ret;    }    return ESP_OK;}
每次运行都会报错：Code: Select all
I (14276) GATTC_GATTS_COEX: GATTC unregisted.E (14276) BT_APPL: Deregister Failed unknown client cifE (14276) GATTC_GATTS_COEX: unregister_gattc gattc unregister failed, error code = ffffffffI (14286) GATTC_GATTS_COEX: BLE closed.W (14296) BT_APPL: bta_dm_disable BTA_DISABLE_DELAY set to 200 ms
请问是什么原因？