I think there are 3 bugs:
1) When any user try to upload any file on forum post, an "un-approaved" forum post is created by default in the topic.
2) When any user try to post any blog post and attach files to the blog post - an "un-approved" empty blog post is posted by default before even making the blog post publish.
3) In case any one from developement team denies that the above 2 are not bugs and they are BY DESIGN. Well, in any forum post or blog post is being posted and still not published by the user, the activity feed still show the updated that this file has been uploaded and it is visible to public even when the original forum post or blog post is not made public or published or not even save by the user. Just by uploading a file, it added an entry to the activity feed which is a bug.