For some reason, it keeps randomly removing people off my social favorites list, at least it seems to do so with the first favorite list, the other two don't seem to have that issue from what I saw.
I've checked if I was unfriended but no, I wasn't. I looked up the user (sometimes they were online as well) and re-added them back onto the list, and eventually it removed them again. I know that because my first list is always full so when it is 31/32, it's pretty easy to see something happened. Today, it was went down to 26/32 without anyone unfriending me and without me removing anyone.