The innovation of the seated person greeting the one who enters, and likewise addressing the greeting individually to each person in the gathering.

The Shaykh : Excuse me... Before we hear the questions and their answers, I want to clarify to you that word which surprised you, or some of you, and that is my saying that this is a religious innovation.
In truth, I believe that the most important thing that a person who has some knowledge should care about is dealing with the new, emerging matters that have no connection to the Book and the Sunnah. Addressing these emerging matters that circulate among people, while no one points out their occurrence or their nature as religious innovations, is the type of matter that people should be reminded about and warned against. We know from the Sunnah of the Messenger of Allah (peace and blessings be upon him) that the standing person greets the seated person, and that the few greet the many, as stated in Sahih al-Bukhari and others. Therefore, when the one who enters comes in and offers his greeting to the seated people present, the seated people only need to return the greeting, either in kind or better, as stated in the Noble Qur'an. As for the seated person saying, "Peace be upon you," or "Peace be upon you all," this is, of course, contrary to the Sunnah. This is the first point.
Second: This occurs with some groups or individuals. When the one who enters comes in and wants to complete the Sunnah by shaking hands, he in turn greets and offers a greeting to each person he shakes hands with, saying, "Peace be upon you," "Peace be upon you." This greeting has become a slogan for some Islamic groups today, and this is due to their distance from the Sunnah. So I wanted to mention this religious innovation and that one, for the reminder benefits the believers.