Take a look at this:
Until now I've gotten the per-site total (like in yesterday's heading) even if I only gained rep on one site. What happened here?
(If I gain rep on another site today and that changes the behavior here, I'll update.)
Update (2014-12-27): tonight I was greeted with this, but yesterday for a while I saw the behavior previously described (rep change on one site, site not called out):