After some investigation, I'm not sure why those tags are showing. You look to be using an older version of JFBConnect. There have been many updates in the latest releases (v6.0 is the latest release). It's likely that issue was fixed along the way, but I don't know what the change would have been since I'm really not sure what's causing it on your site.
From a look, it seems the meta description tag from K2 is including our social tags. Generally, re-ordering the plugins should work. If not, the only suggestions I'd have are:
1) Upgrade to the latest release, or
2) Set the positions of the buttons to "Bottom" in the JFBConnect -> Social area. That will make them not be at the top of the article and K2 shouldn't use them as the meta description them.
I hope that helps,
Alex