That isn't a shadowban. That's just the regular spam filter. A shadow ban is a slightly different approach. A shadowbanned user, when logged in can see his posts and comments as if they were there normally, but only he can see them. Other users don't even know about the existence of them. (Mods can see shadowbanned user comments and posts in their subreddits, but normally don't approve them because each post/comment has to be approved manually.)