I looked for the article you mentioned, but couldn't find it either. However, search engines are most likely to treat each link individually, ignoring the nofollow link and following the unmarked one.
Think of it in terms of this scenario. Let's say you have a blog post page that mentions a website in its copy and includes a link. On the bottom of the page, you're displaying an ad banner, leading to the same website. The first link is organic, the second is paid. You would nofollow the ad link, but you still want to pass link juice to the site organically. This is an infrequent scenario, but it illustrates how this path can be applied in practice.
Of course, the best way is to test, especially if you own two web properties. Create a page on Site 1 with two links to Site 2, containing different anchor copy, one follow and one nofollow. Wait for the page to be crawled. Then go to your Site 2 analytics and see which link shows up as referrer. (There are other ways you can structure such a test, this is just one path.)