"Override WordPress discussion settings" – switches both FB and WP comments OFF

Hi there, this is weird, but… I have “Use Facebook for comments” checked. And “Override WordPress discussion settings” check switches off both FB and WP comments.

When “Override” is unchecked, both comment boxes appear side by side, like now, for example http://sixtyandme.com/stretch-yourself-with-these-6-fantastic-yoga-tours/.

Could you please advise? I would love to leave just FB comments option.