Timer3 Interrupt with compare with pin toggle - time is varying

Question

Hi there. 
 I'm using nRF5 SDK 17.1.0 with nrf52840. 
 I've configured my timer3 to interrupt by compare with 10us ticks. When it does, I toggle a pin. But when I measure the high and low periods of the pin with osciloscope, high period is shorter than low (high=8.4 us, low=11.6 us) , and I don't know what may be happening. 
 Does anyone know why it's happening? 
 
 #define OUTPUT_3_PIN NRF_GPIO_PIN_MAP(0,13)

void Gpio_Config(void){
 
 nrf_gpio_cfg_output(OUTPUT_3_PIN);
}

void TimerSpeed_Config(void){
 uint32_t time_ticks;
 uint32_t err_code = NRF_SUCCESS;

 nrf_drv_timer_config_t timer_cfg = NRF_DRV_TIMER_DEFAULT_CONFIG;

 err_code = nrf_drv_timer_init(&TIMER3, &timer_cfg, Timer3_EventHandler);
 APP_ERROR_CHECK(err_code);

 time_ticks = nrf_drv_timer_us_to_ticks(&TIMER3, 10);
 nrf_drv_timer_extended_compare(&TIMER3, NRF_TIMER_CC_CHANNEL3, time_ticks, NRF_TIMER_SHORT_COMPARE3_CLEAR_MASK, true);

 nrf_drv_timer_enable(&TIMER3);
}

void Timer3_EventHandler(nrf_timer_event_t event_type, void* p_context){
 switch (event_type){
 case NRF_TIMER_EVENT_COMPARE3: 
 {
 nrf_gpio_pin_toggle(OUTPUT_3_PIN);
 }
 }
}