[piusv]

I believe Repent and Believe is referring to matters of discipline when he uses the term "practices". Here is what Pius IX said in 1864 in his encyclical Quanta Cura:

Nor can we pass over in silence the audacity of those who, not enduring sound doctrine, contend that “without sin and without any sacrifice of the Catholic profession assent and obedience may be refused to those judgments and decrees of the Apostolic See, whose object is declared to concern the Church’s general good and her rights and discipline, so only it does not touch the dogmata of faith and morals.” But no one can be found not clearly and distinctly to see and understand how grievously this is opposed to the Catholic dogma of the full power given from God by Christ our Lord Himself to the Roman Pontiff of feeding, ruling and guiding the Universal Church.

[Campion]

That doesn't get me to the proposition that no true Pope will ever promulgate any harmful discipline / practice. Pio Nono says we have to obey it (well, if it applies to us) if we're going to continue to call ourselves Catholics.

[ebb tide]

not enduring sound doctrine

When was the last time you heard "sound doctrine" coming from Bergoglio?