Incorrect mouse pageX position on chrome macOS

I don’t know if this is a bug in the browser or if this is the correct behavior.

The chrome browser on macOS for the example below returns pageX starting from 9 coordinate pixel but should start at 10, ending on 109 but should end at 110. An identical example on firefox browser returns the correct values. What could be the cause?

<div class="rect"></div>

body{
  margin: 0;
}

.rect {
  display: block;
  width: 100px;
  height: 100px;
  background-color: red;
  position: absolute;
  top: 10px;
  left: 10px;
}

  document.querySelector('div').addEventListener('mousemove', ({ pageX, pageY }) => console.log(pageX, pageY))

Fiddle.

I expected to get the correct coordinates the same as those returned from the getBoundingClientRect() method.