I noticed an issue with this on a site a week or so ago, and have confirmed this plugin is the culprit by deactivating it. I’d like to reactivate!
I’m only using the icons to link out to facebook, etc. and not using the sharing buttons for posts, but the plugin is writing in the facebook open graph tags anyway. I’m handling those with Yoast.
As a result, the open graph tags are written twice, causing errors. For example the facebook open graph object debugger reports additional instances of og:url.
Additionally, the text the facebook scraper picks up from this plugin’s open graph tags is a long string without spaces that includes link information directly from the content. It looks like all the spaces and html are stripped out.
Yoast grabs the custom excerpt that I prefer for the description, but the og:description tag is duplicated by this plugin, facebook is using it instead.
I like your plugin (thanks for your hard work!), but I think the open graph tags should only be written/output if someone is using the share buttons for the posts. If you add a conditional to that effect, that should cure the duplicate tag issues.