I had the same problem as the OP — AddtoAny showed up on my main page, but not on the individual posts. And, of course, if you try to share from the main page, you end up sharing your blog URL rather than the post (not so good).
In light of the comments above, I suspected is was an HTML customization issue, and since it was working fine both before the upgrade and before I started using YUI compression on Autoptimize (which I turned on last night), I simply unchecked the YUI compression box.
Fortunately, that = Problem solved.