Fatwa of Sheikh Saalih As-Suhaimi hafidhahullah:

Question: The second question is, is it permissible for a Salafi student of knowledge to go and give lectures or participate in seminars at institutes that are generally okay but they have issues which go against the Shari’ah, such as the issue of Hizbiyyah in particular. So do I deliver (a lecture) with them; meaning, if there is a knowledgeable student, do they give lectures to them? Answer: Yes, but with three conditions. The first: it should not be on one of their special occasions, such as celebration of the Prophet's birthday, or during events commemorating some of the figureheads of Hizbiyyah in this era, and so on. The second condition is that he (the one delivering the lecture) has mastered the subject-matter that he wants to speak about. And the third condition is that they (the hizbi institute) does not exploit this as a means to increase their numbers. So if you think that the most likely outcome is that they will say: “By Allah, we were visited by Sheikh so-and-so, and so-and-so delivered a lecture with us,” then in this case he should stay away from them and not go near them. Instead, he should look (elsewhere) for those who will benefit from his lectures. Source: https://t.me/madrasatuna/2711