I placed a bounty on it, and it was refunded back in May of 2011. Today it shows up on my Reputation tab as a total rep earning of 212 for the day. It's the only time I've ever hit the rep cap here on meta.
Now, I'm not sure if that should be considered rep earning or not, but I seriously don't think it should qualify for Mortarboard. The badge was issued either on the date or retroactive to the date that the bounty was refunded, and the notification simply went out now.