A Sunni scholar should never sit with people with dodgy positions until they disown their corrupt stances. If he does, his followers begin to see those he sits with as unproblematic. I've seen this first hand. This is about religious events. As for issues of common concern like politics or RSE, let's say, maybe the ulama will allow a Sunni scholar to sit with deviants WITH the condition that he makes his stance clear regarding their heresy. E.g. a Sunni scholar might sit with devbandis regarding RSE but if so, he should make his stance clear that he considers devbandis to be heretics and dev4 to be insulters of RasulAllah ﷺ and that the fatawa of Husam al-Haramayn are correct.