Why are service products configured as not visible for an interface shown to Knowledge Advanced authors logged into that interface?
Oracle Service Cloud, Product listing
The list of service products available to Knowledge Advanced content authors is dependent on two things. First, the View(s) associated with the Console User will each be associated to a list of products, and this list will determine what products are limited from view for Console Users while using the KA Authoring tool. Further, the Content Type associated with the content being viewed or created is also a limiting factor in what will display for available products to associate to a document. Thus, the KA content author can only assign products to an article that are in the intersection of the products in the author's view(s) and the products assigned to the content type.
Interface configurations, including the visibility configured per-interface on service products within the Products/Categories/Dispositions editor in the agent console, does not affect this behavior for Knowledge Advanced. Similarly, view assignments per interface within Knowledge Advanced authoring also does not affect this behavior.
For similar information on categories see Answer ID 9747: Categories not assigned to interface show to Knowledge Advanced authors