Most likely the issue of Naseeruddin's blenders in Aqaid will have cropped up somewhere on social media or a site like this and a Mureed would have seen it and had no answer so mentioned it to Iran Shah who then decided this calls for a sprinkling of falsehood. Word of mouth will have done the rest of the legwork amongst the public. Ulama as we know all to well are of various types, some are sincere and strict, some careless and unprincipled, some fame, money and power driven. Only the first category applied caution on this matter, the rest will have gone with the flow and money. The first time I came across the explanation was from a comment on social media by a Mureed of Naseeruddin who accepted his pir had done blenders in Aqaid but apparently Iran Shah had got him to repent and he also mentioned that till this day there is a ban in Pakistan on printing various books by Naseeruddin because of various dodgy things in them.