What is the interpretation of Ibn Hajar's mention of Al-Daraqutni, Al-Bukhari, Malik, Muslim, and Sufyan ibn 'Uyaynah among the mudalliseen, and what is the meaning of "mudallis"?

Summary: A mudallis (one who practices tadlis) is someone who narrates from a person they heard from, something they did not actually hear from them, using a wording that suggests direct hearing, such as saying "on the authority of so-and-so" ('an fulan) or "so-and-so said" (qala fulan). Tadlis is divided into two main categories: 1. Tadlis al-Isnad (concealment in the chain of narration): This is when the mudallis narrates from someone they met or were contemporary with, something they did not hear from them, creating the impression that they heard it directly. They use wordings like "so-and-so said" (qala fulan) or "on the authority of so-and-so" ('an fulan). 2. Tadlis al-Shuyukh (concealment concerning the teachers): This is when the mudallis describes their teacher using obscure or less known attributes to give the impression that the teacher is someone else or to inflate the number of their teachers. In addition to these, there is Tadlis al-Taswiyah (concealment of equalization): This is when the mudallis narrates a hadith from a weak narrator situated between two trustworthy narrators, so they drop the weak narrator, making the isnad appear continuous.

Some imams, such as Ibn Mandah, who described Al-Bukhari as a mudallis, as well as Al-Daraqutni and Muslim, were accused of tadlis. However, scholars did not agree with these accusations and clarified that such narrations are understood to have firm evidence of hearing from another source. As for Sufyan ibn Uyaynah, he did practice tadlis, but only from trustworthy narrators, and his tadlis was rare and harmless. The situations of those who practice tadlis vary. Some of their hadith are accepted because they are trustworthy and their tadlis is rare. Others only practiced tadlis from trustworthy narrators. Some, whose tadlis from weak or unknown narrators was frequent, their hadith is not accepted as proof unless they explicitly state direct hearing. And then there are the weak narrators whose hadith is not accepted as proof at all, due to their weakness being exacerbated by tadlis.