watchdog reset after PWM

Question

Hello, 
 I'm playing beep sound using pwm1 (timer1). 
 The onSound() starts beep sound. 
 The disableBuzzer() terminates pwm1. 
 The handler_buzzer() selects continuous sound playback or pwm1 termination. 
 
 Abnormal condition with log message 
 
 
 
 The "buzzer stop" does not occur and the watchdog reset(2 sec) occurs intermittently. 
 
 
 Even if "buzzer stop" is output, there is no buzzer sound and watchdog reset (2 sec) occurs intermittently. 
 
 
 I am wondering if there is a problem with the code.
I use nrf51822/SDK 12.1.0.
I need help. 
 thanks. 
 void onSound(uint8_t Num)
{
	NRF_LOG_PRINTF("buzzer start
");

//	offSound();
	BUZZER_USE;

	if(Num != BEEP_DOOR_ALARM)
 doorAlarmBeepCnt = 0; // door open alarm beep cancel

	beepOrder = 0;
	beepCnt = beepCntInfo[Num];
	soundNum = Num;

	makeSound(beepLevel[soundNum][beepOrder]);
	controlLed(ledInfo[soundNum][beepOrder]);
	timerBuzzer(START, beepTime[soundNum][beepOrder]); 
}

void disableBuzzer(void)
{
	ret_code_t err_code;

	timerBuzzer(STOP, NULL); 
	app_pwm_disable(&PWM_BUZZER);
//	err_code = app_pwm_end(&PWM_BUZZER);
//	APP_ERROR_CHECK(err_code);

	nrf_gpio_pin_clear(BUZZER_PIN);
	nrf_gpio_cfg_output(BUZZER_PIN);

	BUZZER_NO_USE;
	NRF_LOG_PRINTF("buzzer stop
");
}


void makeSound(uint16_t level)
{
	ret_code_t err_code;

	err_code = app_pwm_uninit(&PWM_BUZZER);
//	APP_ERROR_CHECK(err_code);
//	app_pwm_disable(&PWM_BUZZER);
	app_pwm_config_t pwm1_cfg = APP_PWM_DEFAULT_CONFIG_1CH(level, BUZZER_PIN);
	pwm1_cfg.pin_polarity[0] = APP_PWM_POLARITY_ACTIVE_HIGH;

	err_code = app_pwm_init(&PWM_BUZZER, &pwm1_cfg, NULL); // callback_pwmBuz);
	APP_ERROR_CHECK(err_code);
	app_pwm_enable(&PWM_BUZZER);

	// sound level check
#if !TEST_SOUND_OFF
	if(fireStatus)
 while(app_pwm_channel_duty_set(&PWM_BUZZER, 0, SOUND_MAX) == NRF_ERROR_BUSY);
	else if(batteryStatusSave <= BATTERY_LOW)
 while(app_pwm_channel_duty_set(&PWM_BUZZER, 0, SOUND_MIN) == NRF_ERROR_BUSY);

	else if(soundLevelTemp == 0)
 while(app_pwm_channel_duty_set(&PWM_BUZZER, 0, soundLevelInfo[lockInfo.soundLevel]) == NRF_ERROR_BUSY);
	else
 while(app_pwm_channel_duty_set(&PWM_BUZZER, 0, soundLevelTemp) == NRF_ERROR_BUSY);
#else
	while(app_pwm_channel_duty_set(&PWM_BUZZER, 0, SOUND_OFF) == NRF_ERROR_BUSY);
#endif
}

void handler_buzzer(void * p_context)
{
	UNUSED_PARAMETER(p_context); 

	beepOrder++;
	beepCnt--;

	if(beepCnt)
	{
 timerBuzzer(START, beepTime[soundNum][beepOrder]); 
 makeSound(beepLevel[soundNum][beepOrder]);
 controlLed(ledInfo[soundNum][beepOrder]);
	}
	else
	{
 disableBuzzer();
 soundLevelTemp = 0;
 }
 
 
}