Giang,
Sorry for the delay in getting back to you. I wanted to let you know we're looking into this. It seems to be an issue with how we're doing the OG tags in EasyBlog. Basically, the plugin isn't trying to set the tags even though those options are there to select where the description should come from.
It may take a week or so to get you a good answer/solution. If you need more information or it becomes urgent to fix sooner, let us know, and we'll see if we can speed things along. There's some changes that we're looking into for all of our Open Graph plugins as well as working on the next v5.1 release of JFBConnect.. so there's a lot of good stuff coming, just need to finalize it all.
Thanks,
Alex