Buffer say that they lost nearly half of their social referral traffic in the last year. I’m going to do one of those annoying things and not answer the question I pose in the title. I don’t have access to Buffer’s data so I can’t give you any real insights.
What I will do is give you some ideas about how to dig deeper into these kinds of “oh my!” moments that you find in your analytics data. Sometimes it’s too easy to take figures at face value, panic and draw the wrong conclusions.