Is one halachicaly required to remove every last crumb of challah that has fallen on their plate before placing hot (non-liquidy) cholent, or chicken on it on Shabbos. Although a davar gush has the status of a kli rishon, and is able to ‘cook’ other foods, it is not the same entirely as a real kli rishon. While one may not put a baked item into a kli rishon even once it is removed from a fire, is there a halachic prohibition to put the food down if there are crumbs there, or is it a chumra to be careful with this?
R’ S. Z. Auerbach held that there is no need to be careful about this, and he called it a chumra yiseira (overly stringent). His reason was because the person has absolutely no intention to cook the crumbs, and the concept that the cholent will cook something in a kli sheini because it is considered a solid is also a chumra (we are careful about it, however it is nevertheless considered a chumra). Additionally, the crumbs are dry, and the question would only be because of bishul after baking, and it is doubtful that the crumbs are indeed getting cooked this way.
Shulchan Shlomo 318 comment 37 on sief katan 29.