Maybe, but there are perfectly legitimate reasons for such functionality. It is essentially the same as the NYT paywall. It looks bad when someone clicks a link

Maybe, but there are perfectly legitimate reasons for such functionality. It is essentially the same as the NYT paywall. It looks bad when someone clicks a link in a tweet only to be told that they aren't allowed to access the content until they take additional steps (either buying a subscription or making an account). So they provide links to bypass the restrictions when they are shared over social media. Can this be used for SEO abuse? Probably, though I couldn't tell you how.