Moderators, or admins, don't get any special treatment when posting

What can happen is that while you are typing a reply, somebody else might also be typing a reply and have pressed the submit button before you. That should not cause double posting, though it can jumble about where your post ends up because your reply will be pushed down one post.
If you need to delete a post you can't delete yourself, you can use the exclamation icon in the top right of the post to report it to the moderators and request them to delete it.