Pius VI, famous for being kidnapped by the self-crowning Emperor Napoleon, condemned 85 propositions of Ricci’s False Synod of Pistoia which resembles in many’s Vatican II. The heretical propositions resemble many of those issued by Vatican II, and after Vatican II especially those of a liturgical and sacramental nature. “Table” instead of “altar”, Holy Communion under both species, etc.
Possible?
Yes, Vatican “self-limited” the magisterial weight of its own teaching authority when it stated when asked:”pastoral” for the texts, and infallible in its notes when it restates already defined teachings of previous infallible council. Ref. “Rhine Flows Into the Tiber”, Fr. Wittgen, SVD.
Kind of like saying: “I’m a pole vaulter. As my first rule, no poles are allowed.”
Kind of defeats the purposes as infallible extraordinary councils are only called in response to grave attacks against the Faith of the Church by heretical and/or schismatic groups masquerading as true Catholics. Councils are only called in grave necessity and only to condemn heresy.
For example, Council of Trent> the dogma of transubstantiation to clarify Real Presence due to Protestant heresies.
Here an infallible codification and definitive reiteration of our apostolic faith, in extremely detailed doctrinal form, was needed to counter heretical Protestant attacks on the priesthood, the Holy Sacrifice of the Mass, and on the Blessed Sacrament of the Altar that threatened the very existence of the Catholic Church. Every historical council has anathematized doctrinal error, or excommunicated schismatics except Vatican II. The goal of a council is to be dogmatic, to be infallible so that the good wheat can be easily discerned from the chaff which is then burnt.
Vatican II : “Chaff, Wheat, equally good, right?! Stop being so judgemental: let’s dance! Make love not war.”