WordPress version: 3.5
WordPress SEO version: 1.3.4
When using the %%SEP%% tag in the title, the title tag looks just fine, using the separator defined in wp_title(), but on the og:title it always uses '-' as the separator. If you go and change %%SEP%% into another thing it works, though...
I don't think that Facebook has any blocks on using different characters, an it would be great to change it in just one place.