First of, thanks for the recent update of the plugin, Chad.
The "Add link to facebook" plug-in collides w/WP-Members. If you are on a Login/Edit/Register page, all of that page's information is printed above the header, directly under the canonical link if you examine the source code. Don't know if it does the same for the sidebar widget.
For example:
<link rel='canonical' href='http://www.xyz.com/manage-profile' />
<ul>
<li><a href="http://www.xyz.com/manage-profile?a=edit">Edit My Information</a></li>
<li><a href="http://www.xyz.com/manage-profile?a=pwdchange">Change Password</a></li>
</ul>
<meta property="og:title" content="Manage Profile" />
Underneath this is the rest of the meta properties generated for Facebook.
Deactivating "Add link to Facebook" makes the problem go away, but I really don't want to lose that plugin. I am posting this info on that author's site as well.
I don't know if there's anything you can do; I just wanted to let you know for informational purposes.
Thanks,
Tim