Is the rule of explicit mention of hearing applied to all levels of the chain of narration for everyone described as practicing concealment?

The student : Regarding what you mentioned, Shaykh, about the condition of al-Walid ibn Muslim explicitly stating that he heard the report in all levels of the chain.

The Shaykh: Yes.
The student : So, this rule can be applied to any hadith or the hadiths that a hadith scholar wants to declare defective, meaning, did you find some of your hadiths to which this treatment is not applied?

The Shaykh : This is correct, as we always do with al-A'mash's use of "from," for example, and he is one who practiced concealment. But we overlook his concealment because of his high status and knowledge, and so on, unless it becomes clear that there is something in this hadith, and we investigate and find nothing to hold onto to declare it defective. In that case, we stop at al-A'mash's use of "from." This is, in reality, the way of the early scholars. Therefore, I say that the theoretical study of the science of hadith terminology alone is not sufficient; it must be combined with practical application, because the practical study will reveal to him what does not appear in the theoretical study. And this is, in fact, a matter that encompasses all sciences.