I noticed that, too, but only when I'm reading and commenting from my reading page. When I've expanded a cut and then click on comment, it redirects me to the top of the post.
But when I've opened the post from the subject line and read/comment from there, clicking on comment lets me stay at at the end with the opened comment form.
no subject
But when I've opened the post from the subject line and read/comment from there, clicking on comment lets me stay at at the end with the opened comment form.