Rebbe Nachman of Breslov once said, “The world labors under the misconception that a tzaddik cannot make a mistake. I say this is not so. A tzaddik can make a mistake. The mistake remains a mistake and the tzaddik remains a tzaddik.”
Rebbe Nachman “also said of certain Chassidic leaders of his day, ‘The tzaddikim are making a mistake by praying after the z’man tefillah.'” (Chayei Moharan 487).
Of course, I’m not saying this describes any people known today as gedolim, but there’s also this…
“There are leaders who go by the name of rabbi but whose learning has been picked up from the superficialities' andwaste’ of Torah. They are unable to control even themselves, let alone other people. But they still have pretensions to greatness and seek to lead and guide the whole world. You should be very careful to accord them no recognition whatsoever so as not to add in any way to their power or authority. They themselves can be forgiven for what they do: they are no more than the victims of a strong lust for power. It is the people who give them credibility and power and who are prepared to accord them the title of rabbi who will have a heavy penalty to pay.” (Likutei Eitzos).