We've got a local github installed. Interestingly, despite being setup for gravatars and having all our info input it just shows octocats for everyone. Our gravatars show up in other gravatar enabled applications, so it appears to be some kind of issue with our github install. Anyone else run across this problem and have a solution?
It appears that a Github default configuration change got us during an update. The old version showed gravatars by default. After the update, they disappeared. Ultimately we found a "display gravatar" option, which was off... Turning it on solved the problem.