GPIOTE events firing as soon as they are enabled

Question

I am trying to implement a simple matrix 4X4 keypad. I have an issue in enabling gpiote events. I disable gpiote events when there is a row event and i scan the keys by turining off/on columns and reading the row states. Then i re-enable them. However as soon as i enable there is a new event firing (probably because button is still physically closed) but i set the event lotohi so i'd still expect it to not fire.. 
 Any suggestion is welcome thanks! 
 static const uint8_t column_to_pin_map[4] =
{
 (uint8_t)(KBC_1_PIN),
 (uint8_t)(KBC_2_PIN),
 (uint8_t)(KBC_3_PIN),
 (uint8_t)(KBC_4_PIN),
};

static const uint8_t row_to_pin_map[4] =
{
 (uint8_t)(KBR_1_PIN),
 (uint8_t)(KBR_2_PIN),
 (uint8_t)(KBR_3_PIN),
 (uint8_t)(KBR_4_PIN),
};


static void scan_keyboard_for(uint8_t row_pin){
 
 uint8_t column = NULL;
 uint8_t row = NULL;
 disable_row_events();
 for(uint8_t c = 0; c < 4;c++){
 nrfx_gpiote_out_clear(column_to_pin_map[c]);
 nrf_delay_us(PROPAGATION_DELAY);
 if(!nrfx_gpiote_in_is_set(row_pin)){
 column = 1 + c;
 break; 
 }
 }
 if(KBR_1_PIN == row_pin) row = 1;
 if(KBR_2_PIN == row_pin) row = 2;
 if(KBR_3_PIN == row_pin) row = 3;
 if(KBR_4_PIN == row_pin) row = 4;

 NRF_LOG_INFO("COLUMN: %d ROW: %d", column, row);

 nrf_delay_us(PROPAGATION_DELAY);

 nrfx_gpiote_out_set(KBC_1_PIN);
 nrfx_gpiote_out_set(KBC_2_PIN);
 nrfx_gpiote_out_set(KBC_3_PIN);
 nrfx_gpiote_out_set(KBC_4_PIN);

 enable_row_events();
 //return column;
}

static void gpiote_in_event_handler(nrfx_gpiote_pin_t pin, nrf_gpiote_polarity_t action)
{
 scan_keyboard_for(pin);
}

static void enable_row_events(){
 nrfx_gpiote_in_event_enable( KBR_1_PIN, true );
 nrfx_gpiote_in_event_enable( KBR_2_PIN, true );
 nrfx_gpiote_in_event_enable( KBR_3_PIN, true );
 nrfx_gpiote_in_event_enable( KBR_4_PIN, true );
}
static void disable_row_events(){
 nrfx_gpiote_in_event_disable( KBR_1_PIN );
 nrfx_gpiote_in_event_disable( KBR_2_PIN );
 nrfx_gpiote_in_event_disable( KBR_3_PIN );
 nrfx_gpiote_in_event_disable( KBR_4_PIN );
}

void init_keyboard(){
 if(!nrfx_gpiote_is_init())
 {
 APP_ERROR_CHECK(nrfx_gpiote_init());
 }
 nrfx_gpiote_out_config_t config_out = NRFX_GPIOTE_CONFIG_OUT_SIMPLE(true); // true ==> init high
 nrfx_gpiote_in_config_t config_in = NRFX_GPIOTE_CONFIG_IN_SENSE_LOTOHI(false);//NRFX_GPIOTE_CONFIG_IN_SENSE_TOGGLE(false); // false ==> hi accu = false
 config_in.pull = NRF_GPIO_PIN_PULLDOWN;
 
 APP_ERROR_CHECK(nrfx_gpiote_out_init(KBC_1_PIN, &config_out ));
 APP_ERROR_CHECK(nrfx_gpiote_out_init(KBC_2_PIN, &config_out ));
 APP_ERROR_CHECK(nrfx_gpiote_out_init(KBC_3_PIN, &config_out ));
 APP_ERROR_CHECK(nrfx_gpiote_out_init(KBC_4_PIN, &config_out ));
 
 APP_ERROR_CHECK(nrfx_gpiote_in_init(KBR_1_PIN, &config_in, gpiote_in_event_handler));
 APP_ERROR_CHECK(nrfx_gpiote_in_init(KBR_2_PIN, &config_in, gpiote_in_event_handler));
 APP_ERROR_CHECK(nrfx_gpiote_in_init(KBR_3_PIN, &config_in, gpiote_in_event_handler));
 APP_ERROR_CHECK(nrfx_gpiote_in_init(KBR_4_PIN, &config_in, gpiote_in_event_handler));
 
 enable_row_events();


 NRF_LOG_INFO("keyboard init done");
}