Hmm. Well it has never happened to me before. I have noticed my follower count going down by one on a couple occasions. I assumed it could be a cancelled account or perhaps a controversial comment I made that someone disagreed with. But, for it to go down by two in such close proximity to that post, I hadn't thought it could be anything other than the content of the article itself.

Perhaps I may have jumped the gun and it was nothing to do with the post..
I'm on a lot more followers now than I was the last time I seen it go down by one, so maybe this is a common thing as your number of followers increases.