That's an interesting problem, and I'll look into it. My initial thought is that this might be related to a recent change in how Spring Social is built (I switched it from an old clumsy build that required a Git submodule to one that is a bit more elegant and is the same process used by the Spring Framework proper.) Looking at the date on those snapshots, I've all but confirmed that the new build is related; it was on 4/12/2012 that I did that build switch.
I'll take a look and let you know when it's resolved.
Spring Social Project Lead