While using a Vive headset and controllers, scaling the universe with the grip buttons works just fine in most cases. However, once I have used the Attach command in the Fly tool to follow an object in in motion, attempting to scale the simulation using the grip buttons results in flying away from the object with everything shrinking. Further attempts to scale at this point only continue to cause everything to shrink. Nevertheless, once I have detached from an object, scaling with the grip buttons functions normally.
For example, the issue will occur while attached to Mimas in its orbit in the Saturn with Rings Simulation, but it will not happen while I am not attached to any body.