Is ist intended that the clone brush tool keeps showing the crosshairs at the position first selected as source as long as you don't actually paint? The moment the clone brush tool starts to copy (meaning the brush ist actually painting) the crosshairs are shown at the "relative" position.
In my opinion it's a bit distractive. I'd rathe want to know where from the clone brusch will take the pixels to paint, not where I first set the selection.