mousemove offset X/Y wrong in Chrome when used on a SVG text element

Question

http://jsfiddle.net/g0bq6af6/2/

SVG

<svg height="750" version="1.1" width="830" xmlns="http://www.w3.org/2000/svg" viewBox="925 890 1363 1192">
  <g>
    <text x="975" y="1795" style="font-size: 816px;">foo</text>
  </g>
</svg>

Javascript:

x = document.getElementById('coords');

document.getElementsByTagName('svg')[0].addEventListener('mousemove', function(a) {

  x.innerHTML = (a.offsetX === undefined) ? (a.layerX + ' ' + a.layerY) : (a.offsetX + ' ' + a.offsetY);

});

I bind mousemove on <svg> and print the offsetX and offsetY. When the mouse is on <text> the coordinates are way wrong, ie -755, -925 instead of the expected 215, 114.

layerX and layerY are correct however.

This problem is in Chrome. Opera gives the correct result. IE is still untested. Firefox does not have offset X/Y and gives a correct result through layer X/Y.

Can anyone please explain this?

I have tried using jQuery to achieve it's normalizing effect but the result is same.

UPDATE

I updated the JSFiddle and added a <circle> to demonstrate that this behaviour is for the <text> element only.

View it here: http://jsfiddle.net/g0bq6af6/3/