[r9etb]

Buffy has an almost perfect circular orbit and encircles the Sun at an extreme tilt, at 47 degrees to the orbital plane of the planets as they swing around the Sun...

This is very odd. Circular is no big deal; neither is a 47 degree inclination. It's the combination of the two that need an explanation.

[SunkenCiv]

I do wonder why the article calls it almost perfectly circular, since it ranges from 52 to 62 AU, about 20 per cent. The Moon is on an elliptical orbit where there's about 5 per cent difference between apocenter and pericenter. :')

[Netheron]

Coincidence?

If an object typically has an elliptical orbit of some random eccentricity, sometimes the major and minor axes just work out to be nearly equal.

Wake me when we see a statistical distribution.