I'm experiencing the "Like" button thing now, too.
It seems hit-and-miss. The only reason I was made aware of it is that 4 of my daily readers, 3 of whom are also bloggers on WP, mentioned it to me. All 4 of them have been reading/Liking my blog for months, so it's not a familiarity issue.
It does seem to have coincided with the new display which "hides" some folks who've "liked" a post, and the removal of the "like" option on a re-blogged post in the toolbar at the top.
Again, it doesn't seem to be consistent, since I am still seeing "likes" hit. But when these folks tell me they couldn't Like the post, independently of one another, I have to trust them.
My blog: TWO HEADS ARE BETTER THAN ONE (thabto.wordpress.com).
Thanks for the assistance.