The Kuiper belt object, or KBO, 2004 XR190 (Buffy), discovered during CFEPS  follow-up observations, is a member of a rare class of KBO.  Buffy’s orbital configurations is not easily explained; there is currently, no widely accepted explanation for Buffy’s peculiar orbit. The conditions of the discovery of Buffy and the implications for its orbit are described in the scientific paper: Discovery of a low-eccentricity, high-inclination Kuiper Belt Object at 58AU by Jones et al. (2003).

Buffy, currently 58 times farther from the Sun than the Earth, is on an orbit that, although tilted (inclined) at 47 degrees relative to the plane solar system, is nearly perfectly circular.

A KBOs orbit can be modified from near circular and flat via frequent encounters with the planet Neptune. During these encounters, the KBO receives a gravitational kicks from Neptune and this perturbs the objects orbit; Neptune experiences an equal and opposite force but, due to the large mass of Neptune, its orbit is not significantly altered.

Many KBOs experiencing such encounters have large-inclination orbits.  Buffy, however, never gets closer to Neptune than the equivalent of 20 times the Earth-Sun distance, much too distant an encounter to experience a significant gravitational boost.  In addition, objects whose orbital inclinations grow due to such encounters normally scatter onto highly elliptical orbits.  How did Buffy get into a configuration with little eccentricity, a large orbital inclination and yet no close Neptune encounters?