1991 VG: Artificial satellite which predated human satellite technology still considered "explained"

In 1995 astronomer and astrobiologist Duncan Steel noted that an object in a similar orbit as Earth's was strangely artificial in appearance.

Duncan Steel also at this time noted that:

None of the handful of man-made rocket bodies left in heliocentric orbits during the space age have purely gravitational orbits returning to the Earth at that time...

Duncan Steel's paper, SETA and 1991 VG

Despite this assertion, the scientific community would later accept the 1996 statement of astronomer Jim Scotti as the official "explanation":

My guess is that it is indeed a natural object, but if it is manmade, perhaps it is a Saturn IVB stage from one of the early Apollo missions.
Jim Scotti's article, What is 1991 VG?