Tested this on the original xbox one, PC and xbox one x with different controllers. My crosshair always moves itself downward without any input on the right stick in any game. Sometimes it’s faster, sometimes slower but always downwards. Not in a straight line. I don’t have this issue on PC. Maybe to stupid to google and sorry if this topic has already been solved/discussed.
Set your deadzones (controller settings) higher until your reticule stops drifting.