I've tried several times on several sites over time to get the Hovercards to work; no luck. Once, there was a little movement; but not even that any more. For the record, NO Hovercard plugin works on any of my sites, no matter the theme or the host. And, yes, we run on PHP5.
Additionally, After the Deadline is the one plugin included in the Jetpack that cannot be deactivated, and it is one that really needs to be able to be deactivated. Many of my clients will be overwhelmed by too much info on their profile page, so I prefer to keep that page as clean and uncluttered as possible. Therefore, I have deactivated and deleted all of Jetpack.