Are there any examples of Chazal pointing out a flaw in one of their contemporaries?

Question

The Tanach is replete with examples of some of our greatest leaders and heroes' personal flaws and mistakes (however minuscule they might be when put into proper perspective). These flaws and mistakes are pointed out by Chazal and Rishonim.

My question is do we have an example of Chazal themselves pointing out to the public (through the written word, like in the Talmud for example) a flaw or mistake of someone in their generation?

What prompted my question is this other question (which I am not asking here): Should a modern biography of a Torah personality include episodes that highlight a flaw (or what could be perceived to be a flaw) in the individual? Although an answer to my question being asked here does not necessarily answer this question, it would be a start.

Answer 1

There are quite a few examples of people sinning in the Talmud. Here are a few examples:

Talmud Bavli, Avodah Zarah 17a

And does not one die on renouncing sins other [than idolatry]? Surely it has been taught: It was said of R. Eleazar b. Dordia that he did not leave out any harlot in the world without coming to her. Once, on hearing that there was a certain harlot in one of the towns by the sea who accepted a purse of denarii for her hire, he took a purse of denarii and crossed seven rivers for her sake. As he was with her, she blew forth breath and said: As this blown breath will not return to its place, so will Eleazar b. Dordia never be received in repentance. He thereupon went, sat between two hills and mountains and exclaimed: O, ye hills and mountains, plead for mercy for me! They replied: How shall we pray for thee? We stand in need of it ourselves, for it is said, For the mountains shall depart and the hills be removed!24 So he exclaimed: Heaven and earth, plead ye for mercy for me! They, too, replied: How shall we pray for thee? We stand in need of it ourselves, for it is said, For the heavens shall vanish away like smoke, and the earth shall wax old like a garment.25 He then exclaimed: Sun and moon, plead ye for mercy for me! But they also replied: How shall we pray for thee? We stand in need of it ourselves, for it is said, Then the moon shall be confounded and the sun ashamed.26 He exclaimed: Ye stars and constellations, plead ye for mercy for me! Said they: How shall we pray for thee? We stand in need of it ourselves, for it is said, And all the hosts of heaven shall moulder away.27 Said he: The matter then depends upon me alone! Having placed his head between his knees, he wept aloud until his soul departed. Then a bath-kol28 was heard proclaiming: 'Rabbi Eleazar b. Dordai is destined for the life of the world to come!' Now, here was a case of a sin [other than minuth] and yet he did die! — In that case, too, since he was so much addicted to immorality it is as [if he had been guilty of] minuth. Rabbi [on hearing of it] wept and said:29 One may acquire eternal life after many years, another in one hour! Rabbi also said: Repentants are not alone accepted, they are even called 'Rabbi'!

Another famous example is "Acher, or Elisha Ben Avuya" Who became a complete heretic, even while he kept close relationship with his teacher R. Meir.

And then there is my favorite story of a Rabbi who was kicked out of Yeshiva for asking a question.

Talmud Bavli, Bava Bathra 23b):

A baby pigeon that is found within fifty cubits of a coop belongs to the coop’s owner [the assumption is that it came from the coop]. If it is found outside the fifty cubits, then it belongs to the finder [the assumption being that it came from the wild]. Rabbi Yirmiyah asked: If one foot of the pigeon is within the fifty cubits and one foot is outside, to whom does it belong?...It was for this that they expelled Rabbi Yirmiyah from the academy.

And there is also a stroy about Rabbi Yeshua who insisted that Yom Kippur was on a day other than the court ruled. And was subsequently embarassed by Rabbi Gamliel over the situation. From My Jewish learning

Granted that, as above, the majority of the sources are late, there are echoes in these sources of a degree of conflict between the Nasi, the representative of the establishment, and certain other scholars. According to the Mishnah (Rosh Hashanah 2:8-9), in a dispute between Rabban Gamaliel II and Rabbi Joshua regarding the exact date of Yom Kippur, Gamaliel ordered Joshua to appear before him on "his" Yom Kippur carrying his stick and his money-bag so as to establish the Nasi's authority. According to a Talmudic account (Berakhot 27b-28a), after further humiliations of Rabbi Joshua by Rabban Gamaliel, the latter was deposed, for a time, from the office of Nasi.

In another Talmudic account (Horayot 13b) Rabban Simeon ben Gamaliel II had a dispute with Rabbi Meir and Rabbi Nathan, resulting in the exclusion of these two teachers from participation in the debates in the House of Learning.

Answer 2

Story in Taanis 20

מעשה שבא רבי אלעזר (בן ר') שמעון ממגדל גדור מבית רבו והיה רכוב על החמור ומטייל על שפת נהר ושמח שמחה גדולה והיתה דעתו גסה עליו מפני שלמד תורה הרבה נזדמן

נזדמן לו אדם אחד שהיה מכוער ביותר אמר לו שלום עליך רבי ולא החזיר לו אמר לו ריקה כמה מכוער אותו האיש שמא כל בני עירך מכוערין כמותך אמר לו איני יודע אלא לך ואמור לאומן שעשאני כמה מכוער כלי זה שעשית כיון שידע בעצמו שחטא ירד מן החמור ונשתטח לפניו ואמר לו נעניתי לך מחול לי אמר לו איני מוחל לך עד שתלך לאומן שעשאני ואמור לו כמה מכוער כלי זה שעשית היה מטייל אחריו עד שהגיע לעירו יצאו בני עירו לקראתו והיו אומרים לו שלום עליך רבי רבי מורי מורי אמר להם למי אתם קורין רבי רבי אמרו לו לזה שמטייל אחריך אמר להם אם זה רבי אל ירבו כמותו בישראל אמרו לו מפני מה אמר להם כך וכך עשה לי אמרו לו אעפ"כ מחול לו שאדם גדול בתורה הוא אמר להם בשבילכם הריני מוחל לו ובלבד שלא יהא רגיל לעשות כן מיד נכנס רבי אלעזר בן רבי שמעון ודרש לעולם יהא אדם רך כקנה ואל יהא קשה כארז ולפיכך זכה קנה ליטול הימנה קולמוס לכתוב בו ספר תורה תפילין ומזוזות

translation from dafnotesblogpost

The Gemora cites an incident with Rabbi Elozar illustrating this theme. R' Elozar b'Rebbi Shimon rode his donkey along the riverbanks, traveling from his yeshiva to Migdal G'dor, his hometown. He was extremely happy, and self-assured having learned so much Torah. Suddenly, he met an exceptionally ugly man. "Shalom alecha, Rebbi," the man greeted R' Elozar b'Rebbi Shimon. R' Elozar b'Rebbi Shimon however, instead of greeting him in return, scolded him. "You -- good for nothing -- how ugly you are! Are all the people in your town as ugly as you?" "I don't know," answered the man, "but maybe you'd like to tell the Craftsmen who made me, how ugly His work is! R' Elozar b'Rebbi Shimon immediately realized that he had made a bad mistake. He got down from his donkey, and bowed down before the man. "Please, forgive me," he begged. "First," answered the man, "tell the Craftsmen who made me, how ugly His work is. Then I will forgive you!" The man walked off, with R' Elozar b'Rebbi Shimon tailing humbly after him. They came to Migdal G'dor, R' Elozar b'Rebbi Shimon's hometown. There, many people came out to greet the great scholar. "Shalom alecha, Rebbi, Rebbi, Mori, Mori," they called. "Whom are you calling Rebbi, Rebbi," the ugly man asked them. "The person who walks behind you," they answered. "If this is a rabbi," he exclaimed, "may there not be too many of them in Yisrael." "Why do you say this?" they asked. "Do you know how he treats people?" he answered, and told them the story. "Even so, forgive him, for he is a Torah giant," the people requested. "For the sake of this town I will forgive him," the man responded, "as long as he promises never to act like this again." R' Elozar b'Rebbi Shimon then entered the shul and the people assembled there. "A person needs always to be as flexible as a reed," he taught them, "and not hard like a cedar." This, says the Gemora, is the reason, the common reed is used as a quill to write the Torah, tefillin, and mezuzos. (20a – 20b

Answer 3

(עבודה זרה יז ע"ב).

ובגמילות חסדים לא עסק ? והתניא, רבי אליעזר בן יעקב אומר: לא יתן אדם מעותיו לארנקי של צדקה, אלא אם כן ממונה עליו תלמיד חכם כר' חנינא בן תרדיון ! הימנוה הוא דהוה מהימן, מיעבד לא עבד והתניא, אמר לו: מעות של פורים נתחלפו לי במעות של צדקה וחלקתים לעניים! מיעבד עבד, כדבעי ליה לא עבד

In short, the Talmud critisize R' hanina for not giving enough charatiy.

(שבת נד ע"ב)

פרתו של רבי אלעזר בן עזריה היתה יוצאה ברצועה שבין קרניה שלא ברצון חכמים

The Mishna (expalind in the Talmud) critisize R' Elazar for not avoiding his neighbor from doing "Hilul Shabat"

(ברכות סב ע"א)

רב כהנא על גנא תותיה פורייה דרב שמעיה דשח ושחק ועשה צרכיו אמר ליה דמי פומיה דאבא כדלא שריף תבשילא אמר ליה כהנא הכא את פוק דלאו אורח ארעא אמר לו תורה היא וללמוד אני צריך

In short, Rav rebukes Caha'ana for hiding beneate his bed for learning how one should behave with his wife in bed (and Cahana thinks it's justified!).