An example of this is 'Abdul-Malik ibn Abi Sulayman; Imam Shu'ba labeled him as (الميزان), and the term "الميزان" among the Hadith scholars is one of the highes

[قال عبد الله: قال أبي: قال شعبة في حديث عبد الملك بن أبي سليمان عن عطاء، عن جابر، عن النبي -صلى اللَّه عليه وسلم- في الشفعة: أخر مثل هذا ودمر. "العلل" رواية عبد الله (1292)] Imam Shu'ba said if he made a mistake like this, he would cancel him out, even though he was a distinguished imam. If you look at the narrations transmitted by 'Abdul-Malik ibn Abi Sulayman, they are in the thousands. How can you abandon thousands of narrations due to one mistake? They don't have one plus one equals... They don't have these calculations. They look at the SEVERITY of the error. They consider the QUANTITY only if these errors are not severe. For example, if there are many minor errorr; a narrator narrates a hundred Hadiths and makes mistakes in sixty of them, they say he is generally weak due to the abundance of mistakes. But this is when these errors are not grave. But if there is one grave mistake, then all his narrations are invalidated, and they do not say, "This is a great imaam, how can you take away his dignity?" The criterion among Ahlus-Sunnah is not to look at these affairs, but rather to look at whether someone has opposed a fundamental principle of Ahlus-Sunnah, even if he is from Ahlus-Sunnah, if he the matter has been clarified to him, he exits from the Sunnah. We are not talking about people of innovation, whose origin is innovation! This is the second category; those who were scholars of the Sunnah but then deviated from the principles of Ahlus-Sunnah, clear mistakes, these would be considered from the people of innovation after clarification. What is the evidence for that? {ومن يشاقق الرسول من بعد ما تبين له الهدى ويتبع غير سبيل المؤمنين نوله ما تولى} "And whoever opposes the Messenger after guidance has become clear to him and follows other than the way of the believers - We will leave him to what he has chosen." Imam As-Saadi, may Allah have mercy on him, explained: "We will leave him to what he has chosen." to mean, we will abandon him. Why is he abandoned? Because he has opposed the path of the believers. And does this opposition to the believer's path have to occur frequently/repeatedly? It can occur with just one opposition, as illustrated in the previous examples. 3rd CATEGORY: In the third scenario, a scholar from among the scholars of the Sunnah makes a mistake and falls into innovation, but this innovation is not as clear as the first scenario, but rather he makes a mistake and falls into an unclear type of innovation. If the truth is clarified to him and he persists, he is then considered to have deviated. Why? Because he has opposed the Sharia. So, the matter is not subject to our desires, but rather it is regulated by the Book and the Sunnah. It is Allah who judges by the Book and His Messenger, peace be upon him, by the Sunnah, and whatever mistake the methodology of the Salaf deems to lead a person to be cancelled out, then indeed, he is cancelled out, my brother. We are not authorised in the religion of Allah to say this person is cancelled out and this person is not, but rather the matter is referred back to the religion of Allah." Source: https://t.me/almanhajussalafi/474