... has ever been recognized as the pope that was an antipope with no one else contesting the seat?

I do not think so. At least once though it was the other way around, an Antipope became Pope when the latter died, the famous Vigilius case. Even though it has been completely solved for a long time just like the Honorius/Liberius case (see St. Bellarmine), it was frequently used by anti-infallibilists, Gallicanists, Counciliarists, Old Catholics and the like. Unfortunately the SSPX joined that train, too.

Personally I think a uncontested Papacy has to be seen as a true Papacy. The first Papacy challenged in modern times was Paul VI., e.g. through the public processions of the Abbé de Nantes. According to Guerard des Lauriers, this event was deciding in making Montini´s papacy morally doubtful because of his lack of intention to be the Pope (the original sedeprivationist position does not hold that the post-Vatican II popes have been formal heretics which is precisely the reason for the creation of this thesis).