In July 1601 Father Gaspar Hurtado, of the University of Alcala, defended as thesis for his doctorate a number of propositions: among them, that ‘It is not de fide that a particular person, e.g. Clement VIII, is the successor of St Peter’. The troubles did not ensue until spring 1602, when an informer complained in a series of letters to the Papal Secretary of State, and still more, after 7 March 1602 when a theologian of the Jesuit College at Alcala, Onate, maintained the same thesis in a public act under the presidency of another Jesuit, Luis de Torres. The Jesuits, in a spirit of reverence, carefully refrained from inserting the name of the reigning Pope.

The thesis bears directly upon our problem, the problem of immutability. For it offers a peculiarly interesting question about the nature of the logically implicit and its relation to moral certainty. Is the belief that this man is the Pope simply a particular contained in a universal, as you deduce that this baptism regenerates from the proposition that all baptisms regenerate? If so, you may argue that it is implicitly revealed and therefore de fide. But this is difficult to maintain. For you are not asserting that you believe this Pope to be the successor of St Peter because all popes are the successors of St Peter: that would be a true particular contained in a universal. You are asserting that this individual man is the Pope: and it appears that you cannot secure the proposition without the inquiries of natural reason comparable to those inquiries which are not immediate but inform us after investigation that Cicero was a man. This premise, whatever ‘moral certainty’ might be attached to it, could not claim the immediate certainty which might alone be held to justify the ‘revealed’ inference. The premise depended on the probable, highly probable, fulfilment of a complex series of practical and mental conditions. It was not easy to demonstrate that he who was accepted as Pope had been validly baptized, validly ordained, and canonically elected without simony.

Is it an Infallible Truth in the Roman Church that Jorge Bergoglio is the Pope? – Minds to the Grindstone (chinglican.synology.me)

Now, if RC Apologists like Trent Horn would apply the same arguments, they do to the Protestant canon (sola scriptura) to his own church then we would have issues such as this.