when replying to a comment, the comment doesn't "save"

in the attached video you can see that i make a comment, I then add a reply, I hit submit. it seems like the comment posts, but it really doesn't. If i expand the reply again, you see that it looks as if it want's to submit again (actually if you hit the submit again, it doubles).

you have to refresh the page after replying to see it as a "saved" reply.