From time to time my users report likes getting lost in Newsfeed. I have experienced this behavior on myself as well.
Checking the Newsfeed on the personal site it is possible to reply to posts as well as pressing the "like" button. Then you can see an "unlike" which indicates that you pushed "like". In addition your name will be displayed in the people-who-liked-this-post-area.
When reloading the personal site it sometimes occurs that a post you liked is ready for being liked again. No "unlike" button and your name is not displayed as a liker near the post.
Has anyone had a behavior like this? Maybe anyone has a hint for me. Social features seem to run perfect beside this.