The xpad driver for xbox controllers seems quite outdated and buggy. The main noticeable problem being that the left-right motion of the left thumbstick is swapped with the left trigger. (both the triggers should be the Z values, and each thumbstick uses X Y values) There is a better xbox controller driver that supports xbox1 and 360 controllers along with guitars called 'xboxdrv' http://pingus.seul.org/~grumbel/xboxdrv/
All USB bugs should be sent to the linux-usb@vger.kernel.org mailing list, and not entered into bugzilla. Please bring this issue up there, if it is still a problem in the latest kernel release.