Weird behavior of onboard LEDs on Seeed Studio XIAO nRF52840

I have the following code:

void setup() {
  pinMode(13, OUTPUT); // green
  pinMode(12, OUTPUT); // blue
  pinMode(11, OUTPUT); // red
void loop() {  
  digitalWrite(11, HIGH);   
  digitalWrite(11, LOW);   
  digitalWrite(12, HIGH);   
  digitalWrite(12, LOW);   
  digitalWrite(13, HIGH);   
  digitalWrite(13, LOW);   

From where I stand, it should lighten LED 11, wait, turn off LED 11, wait, and repeat the same procedure for other components of LED light.

What it actually does: it looks like turn off for LEDs is lagging. It turns on one LED and than proceeds to turning on another LED before turning the first off. Eventually the first one is off, but I cannot predict, when it will happen.

If I do a blink sequence of each component separately, it works okay, though.

Can someone shed some light on this strange behavior, please?

Found the error:
As it is clearly stated in manual, HIGH turns LED off, while LOW turns it on. That’s a bit strange of a design solution, but replacement LOW to HIGH and vice versa did actually work.

HI, you can extend the delay a little, LOW turn on the light is no problem, but to change your circuit connection