The Albaani Site

The Imaam said, “Standing to pray in Ramadan was legislated only to increase one’s closeness to Allaah عزوجل, for that reason we hold that we do not mix Taraweeh prayer with anything to do with knowledge or teaching and so on, rather the night prayer should be pure worship. As for knowledge, then it has its time, and it is not restricted by time but [instead] what is taken into consideration concerning it is the well-being of the people who are being taught, and this is the foundational principle, and what I mean by this is that whoever makes it a habit/custom where they teach the people between every four rak’ahs, for example, during the night prayer, whoever makes that a habit/custom—then that is a newly invented matter in opposition to the Sunnah. But if it is concerning a situation that happened to occur, like what Ustaadh Ibrahim just spoke about and it is not made into a habit/custom then in that case it is ok and permissible and I agree with him in what he mentioned, but I just wanted to point out that this is something which is not to be taken as custom, what is taken as custom/habit is standing for the night prayer …”

Al-Hudaa wan-Noor, 693.

Also see here, here and here.