Just gotta be patient. I think it mostly works the first time but it's inconsistent about showing the comment after it's posted and sometimes just sits as it it's busy. I've opened my profile in a new tab and have seen the comment there while the first one still shows it as still busy.
I've only had it post and show up right away once so far. Half of the other comments have showed as busy, the other half stop processing but don't show the new comment until I refresh.