OnUpdateSelected stoped by second finger

So in my game I have a button that when pressed increments a number. The code looks something like this:

 public void OnUpdateSelected(BaseEventData data)
 {
         if (isPressed)
                 number++;
 }
 
 public void OnPointerDown(PointerEventData data)
 {
          isPressed = true;
 }
 
 public void OnPointerUp(PointerEventData data)
 {
         isPressed = false;
 }

The problem is that when I use a second finger (while the first one is still on the button) OnUpdateSelected stops being called. I know that OnPointerUp isn't called, so isPressed is never set to false but the number isn't being incremented. Does anyone have a solution to this.