I've just been experiencing some strange behavior of og:description in my homepage, where it contains the description set for the last post, instead of the one for the homepage. I've searched several posts here, Yoast's advice on deactivating jetpack features... but nothing.
The only plugin inserting opengraph tags is Yoast SEO, so I was pretty confused. However, I have find something really strange: I'm running WP i18n 22.214.171.124-alpha to have a translated copy of my blog in english. Everytime I was checking the og tags in the spanish version (main version, at domain root). Out of curiosity, I checked the generated source code in the homepage in English, and it was picking a correct og:description tag!!!
I don't know why, but in the translated version, og:description is ok. This is quite good, because I'm suspecting that every time I post a new entry in the blog, the og:description for main page changes, and that's confusing the like button I have in a widget, so it thinks they are different pages to like each time.
I have tried to deactivate all plugins, but it didn't work :(
I just hope this can be a hint for someone more WP-savvy than me, because I think I'm not the only one experiencing this problem ;o)