FREETOS + NUS high throput application crash the BLE stack without error

Question

CONFIGURACION: 
 NRF52 + SDK15 + SD132 + FREERTOS + NUS. 
 I have a task sending many packages to a central. I'm having an aboslutly aleatory behaviour: - At some time (could be seconds or minutes) the tramsmition stops and I start to get NRF_ERROR_RESOURCES. Next, the device is disconnected but I don't get the BLE_GAP_EVT_DISCONNECTED or BLE_GATTC_EVT_TIMEOUT events in the ble event handler. -Besides the device desappears in the scan, I have had tryed to restart advertising without succed. - I'm not receving any error in the peer, and the program is still running correctly, but it looks like the SD is not responding anymore. - I have tried a lot of debbuging strategies and different configuration without succed, the only temporaly solution was a NVIC_system_restart with a timeout in the comunication task. 
 
 Could you give me a clue of what could be happening? Update the sdk could be a solution for this problem? 
 
 I let you two involved functions: ble_transmition_test is the one that I'm using to reproduce the issue. I'm calling it from a freertos task with low priority. 
 
 
uint32_t ble_string_send(uint8_t *data, uint16_t len)
{
	uint32_t err_code;
	uint16_t time_out = 10;
	uint16_t m_len = 0;
	
	if (len == 0)
 return 0;
	
	if (ble_state == BLE_DISCONNECTED)
 return 0;
	
	if (len > m_ble_nus_max_data_len)
 m_len = m_ble_nus_max_data_len;
	else
 m_len = len;
	do
	{
 err_code = ble_nus_data_send(&m_nus, data, &m_len, m_conn_handle);
 time_out--;
	} while ((err_code == NRF_ERROR_BUSY || err_code == NRF_ERROR_RESOURCES) && time_out);
	
	if (err_code == NRF_SUCCESS)
 return m_len;
	else
 return 0;
}

void ble_transmition_test(void)
{
 
	uint32_t i = 0;
	while(1)
	{
 uint16_t len = sprintf((char*) ble_tx_data, "%u,%.2f,%d,[%.1f,%.1f,%.1f,%d],%d
", i, (float) 20.0, 1,0.066, 1.0,2.0,10,90);
 uint8_t retrys = 100;
 while (ble_string_send(ble_tx_data, len) < len && retrys)
 {
 vTaskDelay(20);
 retrys--;
 }
 vTaskDelay(10);
 i++;
	}	
}
 
 /**@brief Function for handling BLE events.
 *
 * @param[in] p_ble_evt Bluetooth stack event.
 * @param[in] p_context Unused.
 */
static void ble_evt_handler(ble_evt_t const * p_ble_evt, void * p_context)
{
 uint8_t err_code;
 switch (p_ble_evt->header.evt_id)
 {
 case BLE_GAP_EVT_CONNECTED:
 m_conn_handle = p_ble_evt->evt.gap_evt.conn_handle;
 err_code = nrf_ble_qwr_conn_handle_assign(&m_qwr, m_conn_handle);
 APP_ERROR_CHECK(err_code);
 ble_state = BLE_CONNECTED;
 break;
 case BLE_GAP_EVT_DISCONNECTED:
 ble_state = BLE_DISCONNECTED;
 break;

 case BLE_GAP_EVT_PHY_UPDATE_REQUEST:
 {
 NRF_LOG_DEBUG("PHY update request.");
 ble_gap_phys_t const phys =
 {
 .rx_phys = BLE_GAP_PHY_AUTO,
 .tx_phys = BLE_GAP_PHY_AUTO,
 };
 err_code = sd_ble_gap_phy_update(p_ble_evt->evt.gap_evt.conn_handle, &phys);
 APP_ERROR_CHECK(err_code);
 break;
 }

 case BLE_GATTC_EVT_TIMEOUT:
 // Disconnect on GATT Client timeout event.
 NRF_LOG_DEBUG("GATT Client Timeout.");
 err_code = sd_ble_gap_disconnect(p_ble_evt->evt.gattc_evt.conn_handle,
 BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);
 APP_ERROR_CHECK(err_code);
 break;

 case BLE_GATTS_EVT_TIMEOUT:
 // Disconnect on GATT Server timeout event.
 NRF_LOG_DEBUG("GATT Server Timeout.");
 err_code = sd_ble_gap_disconnect(p_ble_evt->evt.gatts_evt.conn_handle,
 BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);
 APP_ERROR_CHECK(err_code);
 break;
 case BLE_GATTS_EVT_HVN_TX_COMPLETE:
 send_wait = false;
 NRF_LOG_INFO("Send ends");
 break;
 case BLE_GAP_EVT_ADV_SET_TERMINATED:
 //command_to_hmi.type = HMI_COMMAND_SLEEP;
 break; 
 default:
 // No implementation needed.
 break;
 }
}