I don't know why, but my default position keeps jumping around while using the Rift. The guardian system consequently gets severely thrown off. I've been able to trigger it by bumping the sensors, waving the touch in front of the sensors, and nothing at all. The sensors are in USB 3.0 ports. The Rift itself has a warning saying "USB driver update recommended", but I've already updated it. This has been happening for a while, but I never really noticed it because there was no static reference for the default position.