With the options you have set, you should NOT see atw classes on the generated output from a [show_posts].
By default, when used with a Weaver theme, the Weaver native post display code is used, and you will get all the normal Weaver classes around the post. The point is to make the posts match the other theme posts.
If you don’t want this, then there is an option on the first option block of Show Posts to NOT use the Weaver theme post display code.