I am having the same issue at http://www.passagepillows.com. This seems like it may be an ongoing issue with the plugin.
WordPress version: 3.5.1
WordPress SEO version: 1.3.4.4
I did this:
Checked "Add OpenGraph meta data" on Yoast SEO --> Social.
I entered Frontpage settings for the correct image which the plugin picks up and the description which the plugin does not pick up.
I clicked Save Settings
I went to https://developers.facebook.com/tools/debug/og/object?q=passagepillows.com
I expected the plugin to do this:
Produce a og:description tag.
Instead it did this:
No og:description tag. The Facebook debugger issued the following warning:
The 'og:description' property should be explicitly provided, even if a value can be inferred from other tags
My website URL is passagepillows.com
Child theme of Twenty Twelve
Still an issue after removing all other plugins.