The latest Twitter updated added retweet and fav buttons to the timeline. It also added a follow button that has apparently been causing a ton of unwanted follows.
Tim Haines, founder of Favstar noted last week that this is causing a lot of follow/unfollow activity, which may explain why it could have happened to you the past two weeks.
My advice to you? Be careful when swiping or else you could be the next victim of an accidental follow!
Via Home Alone / giphy.com