Board Thread:Boruto Discussions/@comment-27639227-20161015120521/@comment-25122992-20161015121201

Well, in volume 1 of the Boruto manga there were given the profiles of the main characters with their natures and techniques, where Yin Release is listed among Sarada's elements along with Lightning (which she also never displayed in the series). Read the references more carefully, they almost always give the source.

But personally, I don't find it surprising, since Sharingan wielders often have an affinity to genjustu which falls into Yin Release category, although Sarada hasn't shown any genjutsu use yet (though it's mentioned in her profile as well).