Hmm, seeing as I know your new board URL, I thought I would try this...
That part generated from the sites meta description tag.
That means it's picking up the default XenForo meta description from somewhere.
Did you perhaps try to share the page while the board still had its default meta description? If so, Facebook will have cached it. And I mean SUPER cached. The Facebook cache is horrible. It could stick for ages.
You are absolutely right. I remember trying out the "share page" function earlier today. At that time my board had the old meta description I know for sure. A few hours ago I changed it. But so far Facebook is showing me the same description. I just pasted a link on Facebook now with the same result as before. Will the cache ever let go of the obsolete meta description?
I wish I would have known some of the effects of messing around with Facebook. It would have helped.
I ran the very specific URL which wasn't correct earlier through the debugger tool. This time the meta description was presented correctly and when I ran the same URL from within my FB account again the meta description was there My conclusion is, based on this article (http://umairj.com/146/how-to-clear-facebook-shares-cache/) that you can update the cache with this tool.