When the include (or blog) plugin is used with the inline flag, it should avoid including any section tags which includes section tags from nested included pages either from an include syntax in the included page or from a blog in the included page.
A possible fix for this could be modifying the included blog and include instructions to include the inline flag if it is set for the current include. Another way could be to make the flags globally (in the renderer?) available so included pages (and even other plugins) could check that themselves.