That does not seem expected to me… what I mean, it does not make sense.
I have the home page and the center only lists posts, not articles… the taxonomy archive is a subset of the home page. If the homepage only lists posts, then the archive also should only list posts, not suddenly add a whole new custom post type to the display.
But I understand it is not the problem of Types, it is an issue in WordPress.
Still, I have no idea how to modify the query of the archive page